全新版大学英语快速阅读第三册课文

攀登英语网 http://www.5pds.com 提供 Unit 1

Why I Love the City

A lot of my friends are moving out of the city. They 're buying houses in the suburbs

because they want to get away from the noise, smog, traffic, and crime of the city. One friend says, \much air pollution in the city. I prefer the suburbs, where the air is clean.\Another friend complains about the traffic: \a parking place, and the traffic jams are terrible.\full of criminals. I rarely leave my house at night—it's too dangerous.\

Before my friends move out of the city, they usually recite the advantages of suburban

life: green grass, flowers, swimming pools, barbecues, and so on. Yet after my friends have lived there for a year or so, they realize that suburban life is not so pleasant as they were expecting. What causes this change? Their gardens! They soon learn that one unavoidable part of suburban life is yardwork. After they work all weekend in their gardens, they 're much too tired to take a swim in their pools or even to cook some meat on their barbecues. And they have another complaint: they can't live in the suburbs without a car. Most of my friends moved to the suburbs to avoid traffic, but now they have to commute to work downtown. They sit on a busy freeway two hours every day!

My opinions about urban life are very different from my friends'—I live downtown?

and I love it! Why? Well, first, I love nature—flowers, green grass, trees, and animals. In the city, I have all the advantages of nature: I can walk through the public park, smell the flowers, and sit on the grass under the trees. I can visit the animals in the zoo. Yet I have none of the disadvantages: I don't have to do yardwork or feed the animals. Also, in the city, I can get everywhere by bus? if there's a traffic jam, I can walk home.

It seems that everyone is moving to the suburbs to avoid the crime of the big cities. I

have a theory about urban crime, however, so I feel safe downtown. The criminal life will reflect changes in society: if people are buying homes in the suburbs, the criminals will soon follow. Criminals want to avoid noise, smog, and pollution, too. Soon, overcrowding and crime will be problems of the suburbs instead of the city!

People on the Move

The history of the American people is, in part, the history of the movement of the

American people. They moved from the colonies of the East Coast to the open spaces of the West. They moved from the country and the farm to the city. More recently, Americans have been moving from the cities to the suburbs.

Open Space; The Move West

攀登英语网 http://www.5pds.com 提供 Pioneer Americans began moving from the East Coast to the West 250 years ago. They

moved west for many reasons. One reason was the availability of unlimited open space and land for farming. Americans liked large open spaces, and they also liked the freedom and independence to develop the land in their own way. Some of the land became farms. Important minerals were discovered in some areas, so some of the land became mines. Other large areas became cattle ranches. There seemed to be enough land for everybody. But it was a difficult life—a life of endless work and hardship.

The Cities

After 1860, the Industrial Revolution changed the United States. Americans learned

how to manufacture steel. They began to produce petroleum. The automobile was invented. Factories of all kinds began to appear, and cities began to grow up around the factories. Farmers and other country people moved to the growing cities in order to find jobs and an easier life. In the early 1900s, the cities were busy, exciting places. However, there was also a lot of poverty and hardship.

The cities grew up—the buildings got taller—and the cities grew out—they spread out

from the center. Private houses with yards and porches disappeared. Apartment buildings, each one taller than the next, took their place. More and more people moved to the cities, and the cities got bigger and bigger.

Some cities could not spread out because there was no room to do so. These cities, of

which New York is the best example, became more and more crowded. More people meant more cars, trucks, and buses, more noise, more pollution, and more crime. Many cities became ugly and dirty. Some people and some businesses began to leave the cities and move to the suburbs outside the cities.

The Suburbs

The move to the suburbs is still happening. Americans are looking for a small piece of

land that they can call their own. They want a house with a yard. However, they do not want to give up the good jobs they have in the city. In many cases, companies in the suburbs give them jobs. In other cases, Americans tend to commute to and from the cities where their jobs are. In recent years, more and more businesses are moving to the suburbs. They are attracting many people and the suburbs are becoming crowded.

What Next?

Americans have watched their big cities fall slowly into disrepair and die. Many

middle-class people have left the cities, and only the very rich and the very poor are staying behind.

Concerned Americans are trying to solve the problems of noise, dirt, crime, and

pollution in the big cities. They are trying to rebuild bad sections of the cities in order to attract and keep business people. They are trying to make their cities beautiful. Now many Americans are thinking of moving back to the cities.

Other Americans are finding that even the suburbs have become too crowded. They are

looking for unpolluted open spaces and for an independent way of life. They are ready to move from the suburbs to the country.

Perhaps Americans will always be on the move.

攀登英语网 http://www.5pds.com 提供

Caution: Bumpy Road Ahead

Students graduating from colleges today are not fully prepared to deal with the \

world.\It is my belief that college students need to be taught more skills and information to enable them to meet the challenges that face everyone in daily life. The areas in which students need training are playing the credit game, planning their personal financial strategy, and consumer awareness.

Learning how to obtain and use credit is probably the most valuable knowledge a

young person can have. Credit is a dangerous tool that can be of tremendous help if it is handled with caution. Having credit can enable people to obtain material necessities before they have the money to purchase them outright. But unfortunately, many, many young people get carried away with their handy plastic credit cards and awake one day to find they are in serious financial debt. Learning how to use credit properly can be a very difficult and painful lesson indeed.

Of equal importance is learning how to plan a personal budget. People have to know

how to control money; otherwise, it can control them. Students should leave college knowing how to allocate their money for living expenses, insurance, savings, and so forth in order to avoid the \ Along with learning about credit and personal financial planning, graduating college

students should be trained as consumers. The consumer market today is flooded with a variety of products and services of varying quality and prices. A young person entering the \suddenly faced with difficult decisions about which product to buy or whose services to engage. He is usually unaware of such things as return policies, guarantees, or repair procedures. Information of this sort is vital knowledge to everyday living.

For a newly graduated college student, the \

he or she is faced with such issues as handling credit, planning a budget, or knowing what to look for when making a purchase and whom to purchase it from. Entering this \world\could be made less painful if persons were educated in dealing with these areas of daily life. What better place to accomplish this than in college?

Memory Lane Isn't What It Used to Be

About this time every year, I get very nostalgic. Walking through my neighborhood on

a fall afternoon reminds me of a time not too long ago when sounds of children filled the air, children playing games on a hill, and throwing leaves around in the street below, I was one of those children, carefree and happy. I live on a street that is only one block long. I have lived on the same street for sixteen years. I love my street. One side has six houses on it, and the other has only two houses, with a small hill in the middle and a huge cottonwood tree on one end.

攀登英语网 http://www.5pds.com 提供 When I think of home, I think of my street, only I see it as it was before. Unfortunately, things change. One day, not long ago, I looked around and saw how different everything has become. Life on my street will never be the same because neighbors are quickly growing old, friends are growing up and leaving, and the city is planning to destroy my precious hill and sell the property to contractors.

It is hard for me to accept that many of my wonderful neighbors are growing old and

won't be around much longer. I have fond memories of the couple across the street, who sat together on their porch swing almost every evening, the widow next door who yelled at my brother and me for being too loud, and the crazy old man in a black suit who drove an old car. In contrast to those people, the people I see today are very old neighbors who have seen better days. The man in the black suit says he wants to die, and another neighbor just sold his house and moved into a nursing home. The lady who used to yell at us is too tired to bother anymore, and the couple across the street rarely go out to their front porch these days. It is difficult to watch these precious people as they near the end of their lives because at one time I thought they would live forever.

The \and goings\of the younger generation of my street are now mostly

\as friends and peers move on. Once upon a time, my life and the lives of my peers revolved around home. The boundary of our world was the gutter at the end of the street. We got pleasure from playing night games, or from a breathtaking ride on a tricycle. Things are different now, as my friends become adults and move on. Children who rode tricycles now drive cars. The kids who once played with me now have new interests and values as they go their separate ways. Some have gone away to college, a few got married, two went into the army, and one went to prison. Watching all these people grow up and go away only makes me long for the good old days.

Perhaps the biggest change on my street is the fact that the city is going to turn my

precious hill into several lots for new homes. For sixteen years, the view out of my kitchen window has been a view of that hill. The hill was a fundamental part of my childhood life; it was the hub of social activity for the children of my street. We spent hours there building forts, sledding, and playing tag. The view out of my kitchen window now is very different; it is one of tractors and dump trucks tearing up the hill. When the hill goes, the neighborhood will not be the same. It is a piece of my childhood. It is a visual reminder of being a kid. Without the hill, my street will be just another pea in the pod.

There was a time when my street was my world, and I thought my world would never

change. But something happened. People grow up, and people grow old. Places change, and with the change comes the heartache of knowing I can never go back to the times I loved. In a year or so, I will be gone just like many of my neighbors. I will always look back to my years as a child, but the place I remember will not be the silent street whose peace is interrupted by the sounds of construction. It will be the happy, noisy, somewhat strange, but wonderful street I knew as a child.

攀登英语网 http://www.5pds.com 提供 Unit 2

Rosa Parks—A Hero of Civil Rights

Most historians say that the beginning of the modern civil rights movement in the

United States was December 1, 1955. That was the day when an unknown seamstress in Montgomery, Alabama refused to give up her bus seat to a white passenger. This brave woman, Rosa Parks, was arrested and fined for violating a city law. However, her act of defiance began a movement that ended the laws that racially segregated America. Because of this, she also became an inspiration to freedom-loving people everywhere.

Rosa Parks was born on February 4, 1913 in Tuskegee, Alabama. Her parents, James

McCauley, a carpenter, and Leona McCauley, a teacher, named her Rosa Louise McCauley. When she was two, she moved to her grandparents' farm in Alabama with her mother and younger brother, Sylvester. At the age of 11, she became a student at the Montgomery Industrial School for Girls, a private school. The school believed that self-esteem was the key to success. This was consistent with Rosa 's mother 's advice to \advantage of the opportunities, no matter how few they were.\

And the opportunities were few indeed. Mrs. Parks said in an interview: Back then, we

didn't have any civil rights. It was just a matter of survival, of existing from one day to the next. I remember going to sleep as a girl hearing the Klan ride at night and hearing a lynching and being afraid the house would burn down.

In the same interview, she explained that she felt fearless, because she had always been

faced with fear. This fearlessness gave her the courage to fight her conviction during the bus boycott. \alone.\

After attending Alabama State Teachers College, Rosa settled in Montgomery, with her

husband, Raymond Parks. The couple joined the local chapter of the NAACP and worked for many years to improve the conditions of African-Americans in the segregated South.

The bus incident led to the formation of the Montgomery Improvement Association.

The Association 's leader was a young pastor of the Dexter Avenue Baptist Church named Dr. Martin Luther King, Jr. They called for a boycott of the city-owned bus company. The boycott lasted 382 days and brought recognition to Mrs. Parks, Dr. King, and their cause. A Supreme Court decision struck down the Montgomery law under which Mrs. Parks had been fined, and outlawed racial segregation on public transportation.

After her husband died, Mrs. Parks founded the Rosa and Raymond Parks Institute for

Self-Development. The Institute sponsors an annual summer program for teenagers called Pathways to Freedom. The young people tour the country in buses learning the history of their country and of the civil rights movement.

攀登英语网 http://www.5pds.com 提供 Best of Friends, Worlds Apart

Havana, sometime before 1994: As dusk descends on the quaint seaside village of

Guanabo, two young men kick a soccer ball back and forth and back and forth across the sand. The tall one, Joel Ruiz, is black. The short, muscular one, Achmed Valdes, is white.

They are the best of friends.

Miami, January 2000: Mr. Valdes is playing soccer, as he does every Saturday, with a

group of light-skinned Latinos in a park near his apartment. Mr. Ruiz surprises him with a visit, and Mr. Valdes, flushed and sweating, runs to greet him. They shake hands warmly.

But when Mr. Valdes darts back to the game, Mr. Ruiz stands off to the side, arms

crossed, looking on as his childhood friend plays the game that was once their shared joy. Mr. Ruiz no longer plays soccer. He prefers basketball with black Latinos and African-Americans from his neighborhood.

The two men live only four miles apart, not even 15 minutes by car. Yet they are

separated by a far greater distance, one they say they never imagined back in Cuba.

In ways that are obvious to the black man but far less so to the white one, they have

grown apart in the United States because of race. For the first time, they inhabit a place where the color of their skin defines the outlines of their lives—where they live, the friends they make, how they speak, what they wear, even what they eat.

\

other 's world.\

It is not that, growing up in Cuba 's mix of black and white, they were unaware of their

difference in color. Fidel Castro may have officially put an end to racism in Cuba, but that does not mean racism has simply gone away. Still, color was not what defined them. Nationality, they had been taught, meant far more than race. They felt, above all, Cuban.

Here in America, Mr. Ruiz still feels Cuban. But above all he feels black. His world is a

black world, and to live there is to be constantly conscious of race. He works in a black-owned bar, dates black women, goes to an African-American barber. White barbers, he says, %understand black hair.\white world meet, he feels always watched, and he is always watchful.

For Joel Ruiz, there is little time for relaxation. On this night, he works as a cashier at

his uncle 's bar in a black Miami neighborhood.

Mr. Valdes, who is 29, a year younger than his childhood friend, is simply, comfortably

Cuban, an upwardly mobile citizen of the Miami mainstream. He lives in an all-white neighborhood, hangs out with white Cuban friends and goes to black neighborhoods only when his job, as a deliveryman for Restonic mattresses, forces him to. When he thinks about race, which is not very often, it is in terms learned from other white Cubans: American blacks, he now believes, are to be avoided because they are dangerous and resentful of whites. The only blacks he trusts, he says, are those he knows from Cuba.

Since leaving Havana in separate boats in 1994, the two friends have seen each other

just a handful of times in Miami—at a funeral, a baby shower, a birthday party and that soccer

攀登英语网 http://www.5pds.com 提供 game, a meeting arranged for a newspaper photographer. They have visited each other 's homes only once.

They say they remain as good friends as ever, yet they both know there is little that

binds them anymore but their memories. Had they not become best friends in another country, in another time, they would not be friends at all today.

Coming to an Awareness of Language

It was because of my letters (which Malcolm X wrote to people outside while he was in

jail) that I happened to stumble upon starting to acquire some kind of a homemade education. I became increasingly frustrated at not being able to express what I wanted to convey in

letters that I wrote ... And every book I picked up had few sentences which didn't contain anywhere from one to nearly all the words that might as well have been in Chinese. When I skipped those words, of course, I really ended up with little idea of what the book said ... I saw that the best thing I could do was get hold of a dictionary—to study, to learn

some words. I requested a dictionary along with some notebooks and pencils from the Norfolk Prison Colony school.

I spent two days just turning uncertainly the pages of a dictionary. I 'd never realized so

many words existed! I didn't know which words I needed to learn. Finally, just to start some kind of action, I began copying.

In my slow, painstaking, ragged handwriting, I copied into my notebook everything

printed on that first page, down to the punctuation marks. I believe it took me a day. Then, aloud, I read back to myself everything I 'd written in the notebook. Over and over, aloud, to myself, I read my own handwriting. I woke up the next morning, thinking about those words—immensely proud to realize that not only had I written so much at one time, but I 'd written words that I never knew were in the world. Moreover, with a little effort, I also could remember what many of these words meant. I reviewed the words whose meanings I didn't remember. Funny thing, from the dictionary 's first page right now, that aardvark springs to my mind. The dictionary had a picture of it, a long-tailed, long-eared, burrowing African mammal, which lives off termites caught by sticking out its tongue as an anteater does for ants.

I was so fascinated that I went on—I copied the dictionary 's next page. And the same

experience came when I studied that. With every succeeding page, I also learned of people and places and events from history. Actually, the dictionary is like a miniature encyclopedia. Finally, the dictionary 's A section had filled a whole notebook—and I went on into the B 's. That was the way I started copying what eventually became the entire dictionary. It went a lot faster after so much practice helped me to pick up handwriting speed.

I suppose it was inevitable that as my word-base broadened, I could for the first time

pick up a book and read and now begin to understand what the book was saying. Anyone who has read a great deal can imagine the new world that opened. Let me tell you something: from then until I left the prison, in every free moment I had, if I was not reading in the library, I was

攀登英语网 http://www.5pds.com 提供 reading on my bunk. You couldn't have gotten me out of books with a wedge. Months passed without my even thinking about being imprisoned. In fact, up to then, I never had been so truly free in my life.

She Wanted to Teach

A railroad was being built all the way down the east coast off Florida, from

Jacksonville to Miami and Negro workers were employed because they were cheap. A great many of them were in Daytona. Most of them had children. They were living in shacks worse than those in The Terry in Augusta. The children were running wild in the streets. Mary Bethune seemed to hear a voice say, \

Her husband, Albertus, wasn't so sure about her school. He thought Palatka was a pretty

good place for them to live. Mary listened but she never gave up her idea. She knew that if she went to Daytona, Albertus would come too.

One day she begged a ride for herself and her little boy with a family that was going to

Daytona. It was only seventy miles away. But in 1904 the sand was deep on Florida roads. Practically no one had an automobile—certainly not the poor family that gave Mary and little Albert a ride. So it was three dusty days after they left Palatka before they reached Daytona. There Mary hunted up the only person she knew, and she and little Albert stayed with this friend for a few days.

As she had done in The Terry in Augusta, Mary walked up and down the poor streets of

Daytona. She was looking for two things—a building for the school she was determined to start and some pupils for that school.

After a day or two, she found an empty shack on Oak Street. She thought this would do.

The owner said she could rent it for $ 11.00 a month. But it wasn't worth that much. The paint had peeled off, the front steps wobbled so that she had to hang onto the shaky railing to keep from falling, the house was dirty, it had a leaky roof. In most of the windows the panes of glass were broken or cracked.

Eleven dollars a month! Mary said she only had $ 1.50. She promised to pay the rent as

soon as she could earn the money. The owner trusted her. By the time she was sure she could have the building, she had five little girls from the neighborhood as her pupils.

What a school! A rickety old house and five little girls! The little girls pitched in and

cleaned the house. The neighbors helped with scrubbing brushes, brooms, hammers, nails, and saws. Soon the cottage could be lived in, but there were no chairs, no tables, no beds. There was no stove. However, there were no pots and pans to cook in, even if there had been a stove. Mary set about changing these things. She found things in trash piles and the city dump.

Nobody but Mary would have thought of making tables and chairs and desks from the old crates she picked up and brought home. Behind the hotels on the beach she found cracked dishes, old lamps, even some old clothes. She took them home too. Everything was scoured and mended

攀登英语网 http://www.5pds.com 提供 and used. \her school had to live up to that motto.

Her little pupils had no pencils. They wrote with pieces of charcoal made from burned

logs. Their ink was elderberry juice. What good was ink or a pencil if there was no paper to write on? Mary took care of that too.

Every time she went to the store to get a little food, or a few pots and pans, she had

each article wrapped separately. The pieces of wrapping paper were carefully removed and smoothed out. The little girls used this paper to write their lessons with their charcoal pencils. She needed a cookstove very badly but she couldn't pay for one. What should she do?

Her little pupils had to have warm food.

Unexpectedly, the problem was solved for her. One day a wrinkled old white neighbor

said to her, \

Mary said, \

\ Mary read the letter to her. \

Mary turned to go. \

The old woman stood by her open door and thought a moment. Then she said, \

old cookstove and I don't need it. Would you want it?\

Unit 3

Black Box Tells Its Secrets

The \

on its surface.

\

technical services superintendent of aircraft electronics. \half the size of a home video recorder, it is bright orange in color so that, in the event of a crash, it can be more easily found. Inside its one-centimeter-thick steel case is a layer of waxy insulating material, three centimeters thick, for extra fire-resistance and to reduce the shock of impact. Inside this is the motor, electronics and 160 meters of magnetic tape which records about 50 aspects of the aircraft 's operation over the previous 25 hours.

\ C over half its surface area

for 30 minutes as well as the weight of very heavy, sharpened spikes being dropped on it. It is almost indestructible. However, in the case of the EL AL aircraft which crashed into a tower block in Amsterdam only minutes after take-off, the device was so badly damaged by the

攀登英语网 http://www.5pds.com 提供 resulting fire and explosion of the plane 's full petrol tanks that the tape could not be played back.

\black box is also fitted with an underwater beacon which gives off ultrasonic

signals when an aircraft crashes into the sea and this signal helps in the search for the location of the crash. In 1974 a TWA Boeing 707 exploded in mid-air above the Ionian Sea near Greece. When the wreckage was eventually found a month later, the black box was found lying on the ocean bed 3km below the sea surface, still signaling,\

The black box was made compulsory for all aircraft in the late 1950's and is located

near the tail of the airplane. It is the safest area as the tail is usually found to be the least damaged after a crash. Next to it is another armored box, the cockpit voice recorder which records everything picked up by a microphone in the cockpit on a tape loop 30 minutes long. The two boxes look very similar and sometimes even rescuers mistake one for the other. At the front is another unit, not designed to withstand a crash. Called the brains of the

system, this flight data acquisition unit collects data from all over the aircraft and compresses it into a single stream of digital data to be sent to the crash-proof recorder.

After a crash and when the black box is found, the accident investigators play the tape

and present their evidence. \been at fault or a bomb could have been placed on board,\says Mr. Hellyer. \the cause, the black box can point the finger of blame.\

\

in maintenance, check each engine 's performance and in other ways. This data will ensure even more safety for passengers and crew,\

Don't Fly with Me

In recent years a new and serious problem has arisen for international airlines and their

passengers. This is the relatively new crime of hijacking. Once an unheard-of event, it has now become a common occurrence. The number of hijacks is increasing and the governments of the world are becoming more concerned about them.

Who are these hijackers? The first ones (about 20 years ago) were usually political

refugees—individuals who simply wanted to leave their country and fly to another. For instance Cubans in America used the hijack technique to get themselves back to Cuba. After the plane had taken off, the hijacker would force his way into the pilot 's cockpit and threaten him with a gun. This technique was often successful, because there is very little the pilot can do in these circumstances. If he refuses to do what the hijacker wants then there is a strong chance that the plane will crash and everyone on board will be killed.

However, more recently, there have been serious developments in hijackers.

Present-day hijackers usually have other motives for taking over a plane. They do not want simply to fly to another destination; they want to use the aircraft and the passengers on board as bargaining points for their political beliefs. They tell the world governments that unless their

攀登英语网 http://www.5pds.com 提供 of the inverse square law for light propagation. I did not have the slightest idea of calculating the distance to the stars. But I could tell that if the stars were suns, they had to be very far away—farther away than 85th Street, farther away than Manhattan, farther away, probably, than New Jersey. The Cosmos was much bigger than I had guessed.

Later I read another astonishing fact. The Earth, which includes Brooklyn, is a planet,

and it goes around the Sun. There are other planets. They also go around the Sun; some are closer to it and some are farther away. But the planets do not shine by their own light, as the Sun does. They merely reflect light from the Sun. If you were a great distance away, you would not see the Earth and the other planets at all? they would be only faint luminous points, lost in the glare of the Sun. Well, then, I thought, it stood to reason that the other stars must have planets too, ones we have not yet detected, and some of those other planets should have life (why not?), a kind of life probably different from life as we know it, life in Brooklyn. So I decided I would be an astronomer, learn about the stars and planets and, if I could, go and visit them.

It has been my immense good fortune to have parents and some teachers who

encouraged this odd ambition and to live in this time, the first moment in human history when we are, in fact, visiting other worlds and engaging in a deep exploration of the Cosmos. If I had been born in a much earlier age, no matter how great my dedication, I would not have known that there were other suns and other worlds. This is one of the great secrets wrested from Nature through a million years of patient observation and courageous thinking by our ancestors. What are stars? Such questions are as natural as an infant 's smile. We have always

asked them. What is different about our time is that at last we know some of the answers. Books and libraries provide a ready means for finding out what those answers are. Stars

A star starts out life from what seems like nothing at all. Stars are born in huge clouds

of gas that are actually far less dense than the space immediately surrounding Earth.

\

that the space shuttle flies through seem as thick as chicken soup,\says Jeff Hester, an astronomer at Arizona State University in Tempe. But because the clouds are so big, they contain a lot of molecules—enough, eventually, to build massive stars.

How big are these clouds that serve as star nurseries? They can be a light-year

across—so enormous it would take light one year to cross one. In contrast, it takes light only one-seventh of a second to travel the nearly 25,000-mile distance that equals the circumference of tiny Earth.

The key to star formation is gravity, says Hester. Gravity causes the multitude of

spread-out molecules to move toward each other and pulls them toward the center of the cloud. \process of star formation. This collapsing process happens relatively quickly (by cosmic standards)—only about 30 million years, or less.

攀登英语网 http://www.5pds.com 提供 Over time the cloud gets smaller and smaller. As the cloud contracts, it also begins to

spin faster. (This is due to a little something called conservation of angular momentum—the same phenomenon that allows a figure skater like Nancy Kerrigan to speed up her spin when she pulls her arms in toward her body. As the mass of gas moves toward the center, the cloud spins faster.) Next, the cloud starts to flatten. \just like when you make a simple pizza,\says Hester. \becomes so strong in the center of the cloud, the center starts to collapse in on itself as it continues to rotate. At this point, you have a disk that's a few times the size of our solar system. (The disk would be about a couple of light-days across, if you 're keeping track of the size of things.) As the disk continues to rotate, matter in the center of the disk starts to move further inward and a big lump forms in the middle of the disk. This lump, says Hester, is a protostar. What happens to the matter that's left over further out in the disk? In our solar system, it

went on to become the planets. (In essence, earth is made up of leftovers.)

Protostars are very hot because so much of the gravitational energy that was once

contained in the loose cloud of interstellar gas has been converted into heat. Protostars are spectacular, glowing with dull red light and infrared light. As a protostar emits this light, it continues to shrink and gets hotter and hotter. Finally, it's hot enough for real star business to begin—nuclear fusion.

At high enough temperatures, atoms slam together at incredibly fast speeds. When this

happens, lighter atoms like hydrogen can fuse together to make heavier atoms like helium. One reaction releases massive amounts of energy; add all the reactions together, and \the energy that makes the stars shine,\star is born.

After a star \on,\he says, its power can cause destruction to the surrounding

environment. A young star expands, tearing apart the cloud that formed it. New stars often break up neighboring stars before they can form. It's hard to overstate what a powerful process star formation is. Even as they are forming, protostars eject huge amounts of material in jets and streams and create violent solar winds.

Unit 5

A Merry Christmas ...

Another Serving?

A Merry Christmas to you all ...

\

large number of British people, then your Christmas will be an alcoholic, rather than a religious, occasion.

攀登英语网 http://www.5pds.com 提供 If you walk down Piccadilly or Oxford Street just before Christmas, you will see an

incredible amount of money being spent on electronic games, bottles of wine, expensive clothes, CDs, cassettes, cameras, and a large number of luxury items. If you walk down the main street of several towns in the Third World just before Christmas, you won't see a large amount of money being spent on presents: in fact, you won't see a large amount of money being spent on anything.

80 % of all disease in the world is caused by bad water supply: for millions of people,

the perfect Christmas present would be a tap in the village square which would give pure, clean, water.

Do we think of these people when we sit down to our Christmas dinner? Of course

not—we 're too busy thinking about the turkey, the roast potatoes, and the presents sitting under the Christmas tree. The whole idea of Christmas now is completely unchristian—I 'm sure that Christ would be furious if he could see what sort of celebrations are being carried out in his name.

So I 'm against Christmas—I agree with Scrooge: \

continue with this wasteful, thoughtless ceremony, then let 's be truthful about it, and call it \—but let 's get rid of the insincere pretence that Christmas is \

Not only for Children?

Recently, a rather sophisticated woman told me shyly that she saves up all her presents

until Christmas morning and then sits up in bed and opens them, just like a child. She thought I would laugh at her and say how silly she was. But in fact I was absolutely delighted to meet someone who treats Christmas as I do.

Many people today have a very different attitude to Christmas. They think it's just a

time when shopkeepers make a lot of money and everyone rushes round buying presents they don't want to give and food they don't want to eat. But have they grown so far away from their own childhood that they can't remember all the good things?

First of all, Christmas takes you out of the ordinary humdrum routine of life. For

children, the fun begins weeks before when the decorations are put up, and excitement gradually mounts as December the 25th approaches.

Everyone seems much friendlier to each other than usual at Christmas-time. You can

lean out of a car window when you 're stopped at the traffic lights and say \and people will smile and respond. You probably wouldn't think of doing that at any other time of the year. Perhaps it's because most people are on holiday or because everyone knows that they are sharing a similar experience. Giving presents can be very satisfying, too, if you plan far enough in advance and really think of the right present for the right person.

Indeed, whatever shopkeepers gain out of Christmas, it is still a \

from which \on non-commercial values.

攀登英语网 http://www.5pds.com 提供 From Your Valentine

Considering the number of ethnic groups that make up the U.S. population, it is not

surprising that Americans have a variety of different holidays. From Thanksgiving to Cinco de Mayo, from Chanukah to the Chinese New Year, they are seldom at a loss for a reason to celebrate. Some of these holidays are rather unusual. Some examples follow.

Groundhog Day, February 2:

The groundhog, a small burrowing animal also known as a woodchuck, is supposed to

come out of his hole to look for his shadow on this day. As the legend goes, if he fails to see his shadow it means spring has come; if he sees it he returns to his hole to sleep, for winter will continue for another six weeks.

April Fool 's Day, April 1:

Don't believe anything you hear on this day of tricks and jokes designed to make you an

\

Halloween, October 31:

After dark, children dressed like ghosts and witches go from house to house shouting,

\children will play tricks on them.

Sadie Hawkins Day, the first Saturday after November 11:

Traditionally, it is the boys who chase the girls, but on Sadie Hawkins Day a girl can

keep any boy she can catch.

On February 14 Americans celebrate another unusual holiday, St. Valentine 's Day, a

special day for lovers. Valentines are cards—usually red and shaped like hearts—with messages of love written on them. Lovers send these cards to each other, often anonymously, on St. Valentine 's Day.

The origins of this holiday are uncertain, but according to one legend, it gets its name

from a Christian priest named Valentine who lived in Rome during the third century after Christ. His job was to perform marriages. for Christian couples. Unfortunately, the Emperor of Rome, Claudius II, did not allow Christian marriages? so they had to be performed in secret. Eventually Valentine was arrested and put into prison. While in prison he fell in love with the daughter of the prison guard.

After one year, the Emperor offered to release Valentine if he would agree to stop

performing these secret marriages. Valentine refused, so the Emperor sentenced him to death. Valentine was executed in 270 A. D. on February 14, the same day the Romans worshiped their goddess of marriage, Juno. Before he was killed, Valentine sent a love letter to the daughter of the prison guard. He signed the letter \ The next valentine was sent in 1415 A.D. Charles, Duke of Orleans sent the valentine

to his wife while he was a prisoner in the Tower of London. His valentine is now on exhibit in the British Museum. The first commercially printed valentines did not appear until 1809. Some of these valentines were not messages of love. Comic valentines, or \

攀登英语网 http://www.5pds.com 提供 were called, were often funny and sometimes insulting. The \in the 1840s when valentine makers started making elaborate and expensive valentines. Jonathan King became famous as a publisher of beautiful and unusual valentines in

Britain in the 1870s. Esther Howland was the first to publish valentines in the United States, in the 1860s. She created handmade designs for valentines, which cost as much as thirty-five dollars.

Today, millions of Americans send and receive valentines on St. Valentine 's Day.

Whether it is an expensive heart-shaped box of chocolates from a secret admirer or a simple handmade card from a child, a valentine is a very special message of love.

Family Rituals

Many American families can boast of certain rituals centered around traditional

occasions, usually holidays. To family members, such small acts seem unremarkable; sometimes, talking about them, they cannot pinpoint when or why the custom began. But social scientists believe that as family life tends to become increasingly fragmented, such repeated ceremonies play a significant role in creating and strengthening our sense of emotional security. Jay Schvaneveldt, a sociologist at Utah State University who has studied hundreds of families, points out that families with the strongest ties have the most rituals. \much for whatever is actually said or done,\—the sense of 'we-ness' that grows out of shared experience. More than anything, the ritual is a symbol of how family members feel about one another.\

There are numerous manifestations of this custom. At Christmas, for example, many

families have special ways of exchanging gifts: \present at a time ... \Or: \children get one package to open on Christmas Eve, and it's always a pair of pajamas.\

Thanksgiving and birthday rituals usually center around food: \wouldn't be

Thanksgiving if Aunt Grace didn't bring her blueberry pie.\privilege of choosing the menu for the entire dinner.\reunions, Sunday prayers, and July Fourth picnics.

But family rituals are just as likely to grow out of spontaneous or chance events. One

woman, without realizing it, started a ritual when she and her husband made a list of their household possessions for a fire-insurance policy. \the job was done I said, 'Well, we know what things we have, but what about intangibles or abstract things?' So we made another list of qualities like love, trust, good health, a sense of humor—what we call our happiness inventory. Now once a year we review it and try to add an item or two to it.\

According to Professor Schvaneveldt, family rituals serve several basic purposes:

Firstly, they reinforce family closeness. A friend of mine prizes the memory of a

childhood event that took place each year on the first warm April Sunday: \out in the yard? breathe in deeply, and say, 'It looks like spring is here at last.' Then I knew that

攀登英语网 http://www.5pds.com 提供 blood when the kidneys fail. She said she suffered from chronic fatigue and blackouts and was losing her balance and her sight. He could already see that she had lost her smile.

\

do? Sit back and watch her die?\

Stevens 's mother was found to be suffering from high blood pressure and was

unqualified to donate a kidney. Her 14-year-old sister offered to become a donor, but doctors concluded that she was too young.

Stevens 's two brothers, 25 and 31, would most likely have made ideal donors because

of their relatively young ages and status as family members. But both of them said no.

So did Stevens 's boyfriend, who gave her two diamond rings with his apology.

\

too afraid.\

Joyce Washington, Jermaine 's mother, was not exactly in favor of the idea, either. But

after being convinced that her son was not being forced to do so, she supported his decision. The transplant operation took four hours. It occurred in April 1991, and began with a

painful X-ray procedure in which doctors inserted a metal rod into Washington 's kidney and shut it with red dye. An opening nearly 20 inches long was made from his groin to the back of his shoulder. After the surgery he remained hospitalized for five days.

Today, both Stevens and Washington are fully recovered. Stevens, a graduate of

Eastern High School, is studying medicine at the National Educational Center. Washington still works for D.C. Employment Services as a job counselor.

\

never played those anyway.\

A spokesman for Washington Hospital Center said the Washington-to-Stevens gift was

the hospital 's first \But there is a shortage of even those kinds of transplants. Today, more than 300 patients are in need of kidneys in the Washington area.

\

said. \needed a kidney, and the child died.\

About twice a month, Stevens and Washington get together for what they call a

gratitude lunch. Since the operation, she has broken up with her boyfriend. Seven months ago, Washington got a girlfriend. Despite occasional pressure by friends, a romantic relationship is not what they want.

\

want to mess up a good thing.\

To this day, people wonder why Washington did it. To some of the men gathered at

Jake 's Barber Shop not long ago, Washington 's heroic deed was cause for questions about his sanity. Surely he could not have been in his right mind, they said.

One customer asked Washington where he had found the courage to give away a kidney.

His answer silenced most skeptics and inspired even more respect.

攀登英语网 http://www.5pds.com 提供 \

Linda 's New Friend

Linda sat on the bottom step of the front porch and double-tied the laces of her running

shoes. She glanced across the street and saw the old man with the cane sitting on his front porch, watching her again. Her family had moved to the neighborhood only recently, and to Linda, it was still a strange and awkward place. \as she jogged past his house. She returned his wave, allowing him only a quick glance. The three miles melted away in the joyous exhilaration that always washed over her as she ran. Rounding the corner of her street, her eyes strayed to the old man, waiting patiently for her return. \

as she concentrated on releasing every ounce of her strength and speed.

\

your power.\fully in the face. She was surprised to see a kind, wistful man, with gentle laughter lines in his face. \What's your event?\

\

me to.\

\

little. My event was the four-hundred meters.\

Just then a gray-haired woman appeared in the doorway. \'m Judith Carr, Linda.

Would you care to come in for some lemonade?\Carr filled lemonade glasses. Linda noticed the late afternoon sun glinting off a shiny object on the wall. She moved closer and saw it was a medallion on an old, faded ribbon. For a moment she did not grasp its significance, but gasped audibly when she did. She looked to see if the Carrs had heard her. The small brass plate below the medal read, \Angeles, 1932. 400 meters. William Carr, United States of America. 46.2 seconds, World Record.\won an Olympic Gold Medal! Linda could not believe her eyes. She looked at the old man, trying to visualize him as the fastest runner in the world. Mr. Carr seemed to sense her puzzlement.

\

front porch and talked the afternoon away. Linda felt more at home in her new neighborhood when she finally crossed the street toward home.

The next morning she sat back in her chair and closed the sports almanac. It was all

there—the story of his unexpected win and the shattering accident only weeks later. The article told what he had done, but it did not tell who he was. Yes, he was Bill Carr, world record holder, but to her he was more. He was a new friend.

攀登英语网 http://www.5pds.com 提供

Unit 7

Starting Your Own Business

Many people, particularly recent college graduates, dream of owning their own

businesses. Although such ventures are often exciting and profitable, the new entrepreneur should thoroughly investigate and plan the situation before plunging in. The first step should be to assemble a board of advisers, including a lawyer, an accountant, and an insurance representative. These individuals can provide valuable information and counsel. Securing the necessary licenses and permits is also a precondition and may require research to determine what is necessary.

Most successful small-business owners have considerable experience in the field

working for others before they become independent. They also begin with substantial financial backing and a good location. Renting space may be preferable or necessary at the start, but the lease on the building must be examined carefully before it is signed. The new owner should be thoroughly familiar with the market and the competition. A person who wants to buy an existing business can often learn the history of the company and its prospects from the owner 's records. Once the business gets started, accurate and complete records should be kept to monitor the company 's progress and profits.

Financing may be the most difficult step for small-business owners. They may rely on

their own savings or borrow money from a bank or the Small Business Administration. Some suppliers will sell merchandise on credit, and manufacturers may be willing to finance the purchase of equipment. If the new business is a corporation, the owner may choose to sell stock. Once the new business is started, the Small Business Administration is a good source of

advice. Several of its programs are designed to help new owners with the advice and expertise of retired executives. A nearby university or trade association may also help owners locate local sources of help.

New business owners often report that they work long, hard hours but find the

experience extremely satisfying. The realization that their efforts will produce actual results in the form of profit, success, and pride can be quite motivating. Those who have worked for others enjoy the opportunity to make decisions and follow projects through to completion. Many report that hard work has never been so enjoyable before. Careful research, investigation, and planning at the outset do not guarantee success, but they provide a good foundation for the new small business and its owner.

攀登英语网 http://www.5pds.com 提供 Ted Turner: His Life and Career

Ted Turner, a fiercely competitive and hardworking businessman, achieved high goals

and great success by the time he was 43 years old. Ted Turner is probably best known for his Cable News Network (CNN), which many people believe has become the global broadcast-news authority. He launched a second nationwide all-news network, Headline News, purchased the Atlanta Braves baseball team, and became the world 's best yachtsman when his boat Courageous won the America 's Cup in 1977. In 1982 Ted Turner was included in the first edition of the Forbes 400 list, naming him one of the 400 richest people in the United States. Turner was named Time magazine's \of the Year\in 1992. How did Ted Turner accomplish all of this at such a young age?

Ted Turner 's father, Ed, grew up in an impoverished family. During the Depression

they lost their cotton farm and were left penniless with no source of income. Starting with nothing, Ed Turner built a billboard company into a successful business. A man of great drive and ambition, Ed Turner was a self-made millionaire who demanded that his only son try to achieve similar success. He instilled in the boy a strong belief that hard work was good. Turner 's father required him to read a new book every two days. Ed Turner also charged his son rent at home during summer vacations from boarding school. Ed Turner was a strong influence in his son 's life.

As a child, Ted Turner lived a very lonely life, often separated from his family. During

World War II, his father served in the Navy. Ed Turner took his wife and daughter with him so they could live nearby but left his 6-year-old son behind in a boarding school in Cincinnati, Ohio. When Ted Turner was in the fifth grade, his father enrolled him in a military academy. Even though Turner had friends at school, it didn't make up for the absence of his parents and sister. Eventually Ted Turner enrolled at Brown University in Providence, Rhode Island. He attended college off and on, became involved in sailboat racing, and became a member of the U.S. Coast Guard for a while. In his early twenties, Ted Turner became general manager of one of his father 's branch offices—the Turner Advertising Company in Macon, Georgia.

Two years later, when his father suddenly died, Ted Turner took over the company. He

soon discovered that he was more skilled than his father in managing the business. A spirited man, Turner exhibited much of his father 's enthusiasm and was strongly determined to become the man his father wanted him to be. Ed Turner had always impressed upon his son how important it was to be a success, but Ted Turner always feared that he would not be able to live up to his father 's expectations. During the next twenty years, Ted Turner worked hard to accumulate enough power and money to fulfill his father 's dream.

Reflecting on his father 's death, however, Ted Turner realized that it was dangerous to

put too much emphasis on material possessions. Rather than devoting his energy only to building an empire, Ted Turner decided to change his life and allow things other than financial success to be his measure of worth. He decided to use his hard-earned influence to serve the public. Concerned about the environment, Ted Turner established the Better World Society in 1985. The purpose of this organization was to produce documentaries to educate people about pollution, hunger, and the danger of building weapons of mass destruction. In 1986 Turner began sponsoring the Goodwill Games to promote world peace by bringing together an

攀登英语网 http://www.5pds.com 提供 assembly of the best athletes in the world to participate in competition during non-Olympic years. The Turner Tomorrow Awards were created to encourage writers and thinkers to focus their attention on solving world problems. The Turner Family Foundation was established in 1992. Board members meet twice a year to decide which charities will receive money donations. Rather than allow ambition and greed to continually define his role, Turner shifted his

attention to global pursuits and environmental issues. By directing his energies toward making life better for others, Ted Turner has discovered a different way to achieve new levels of success.

Working for Fun and Profit

It's a sunny weekend morning. You decide to take a walk. Everything is quiet except for

a group of people and some colorful objects you see about three blocks away. As you get closer, you notice that there are many things lying on the ground: some National Geographic magazines, a collection of toy trucks, some weight-lifting equipment, two bicycles, and a set of chairs. People are parking cars, getting out, and looking over the objects in the driveway. You consider taking a detour around the group of people, but you are curious. Was there an accident? Is this a party? No! Welcome to your first garage sale!

On the same morning, a friend of yours takes a drive. He makes a mistake at an

intersection and takes a wrong turn. He passes a large parking lot full of people, not cars. He sees many multicolored objects. At first he thinks it's an art show. Then he decides it's a fair. He parks his car and gets out to explore. He's just arrived at his first flea market.

Garage sales and flea markets are popular in the United States. Many Americans find

that they can make a little extra money and have fun being \outgrown clothing, appliances, toys, and books and resell them at garage sales and flea markets. Flea markets are generally open spaces in or out of town that become busy sales centers

on weekends. People who want to sell new or used clothing, tools, furniture, or books rent a space for the day for a small amount of money and sell their merchandise. Shoppers from near and far come to get good buys on imported watches, house plants, magazines, microscopes, children 's clothes, and handmade goods such as embroidered pillowcases or jewelry. Some shoppers even buy and sell antiques. They search flea markets for special treasures that they can resell in their own stores for lots of money.

Garage sales are smaller than flea markets, and the merchandise consists mainly of

household items. Dishes, pots and pans, coat hangers, and children 's clothing are inexpensive and common at garage sales. People frequently have garage sales before they move and on weekends when the weather is nice. Sometimes several families gather their unwanted household goods and sell them together: More merchandise attracts more customers.

Cleaning, organizing, pricing, and moving merchandise is hard work, but the popularity

of flea markets and garage sales proves that many Americans work for fun!

攀登英语网 http://www.5pds.com 提供

The Carpet Fitter

Eddie was a carpet fitter, and he hated it. For ten years he had spent his days sitting,

squatting, kneeling or crawling on floors, in houses, offices, shops, factories and restaurants. Ten years of his life, cutting and fitting carpets for other people to walk on, without even seeing them. When his work was done, no one ever appreciated it. No one ever said \the carpet fits so neatly.\

He was especially sick of it on this hot, humid day in August, as he worked to put the

finishing touches to today 's job. He was just cutting and fixing the last edge on a huge red carpet which he had fitted in the living room of Mrs. Vanbrugh 's house. Rich Mrs. Vanbrugh, who changed her carpets every year, and always bought the best. Rich Mrs. Vanbrugh, who had never even given him a cup of tea all day, and who made him go outside when he wanted to smoke. Ah well, it was four o'clock and he had nearly finished. At least he would be able to get home early today. He began to day-dream about the weekend, about the Saturday football game he always played for the local team, where he was known as \the Head\for his skill in heading goals from corner kicks.

Eddie sat back and sighed. The job was done, and it was time for a last cigarette. He

began tapping the pockets of his overalls, looking for the new packet of Marlboro he had bought that morning. They were not there. It was as he swung around to look in his toolbox for the cigarettes that Eddie saw the lump. Right in the middle of the brand new bright red carpet, there was a lump. A very visible lump. A lump the size of a packet of cigarettes.

\said Eddie angrily, \'ve done it again! I 've left the cigarettes under the

blasted carpet!\

He had done this once before, and taking up and refitting the carpet had taken him two

hours. Eddie was determined that he was not going to spend another two hours in this house. He decided to get rid of the lump another way. It would mean wasting a good packet of cigarettes, nearly full, but anything was better than taking up the whole carpet and fitting it again. He turned to his toolbox for a large hammer.

Holding the hammer, Eddie approached the lump in the carpet. He didn't want to

damage the carpet itself, so he took a block of wood and placed it on top of the lump. Then he began to beat the block of wood as hard as he could. He kept beating, hoping Mrs. Vanbrugh wouldn't hear the noise and come to see what he was doing. It would be difficult to explain why he was hammering the middle of her beautiful new carpet.

After three or four minutes, the lump was beginning to flatten out. Eddie imagined the

cigarette box breaking up, and the crushed cigarettes spreading out under the carpet. Soon, he judged that the lump was almost invisible. Clearing up his tools, he began to move the furniture back into the living room, and he was careful to place one of the coffee tables over the place where the lump had been, just to make sure that no one would see the spot where his cigarettes had been lost. Finally, the job was finished, and he called Mrs. Vanbrugh from the dining room to inspect his work.

攀登英语网 http://www.5pds.com 提供 \ \

\madam, as soon as I report to the office tomorrow that the job is done. \

picked up his tools, and began to walk out to the van. Mrs. Vanbrugh accompanied him. She seemed a little worried about something. \his van, laying his toolbox on the passenger seat beside him, \you didn't by any chance see any sign of Armand, did you? Armand is my parakeet. A beautiful bird, just beautiful, such colors in his feathers ... I let him out of his cage, you see, this morning, and he's disappeared. He likes to walk around the house, and he's so good, he usually just comes back to his cage after an hour or so and gets right in. Only today he didn't come back. He's never done such a thing before, it's most peculiar ... \

\

And saw his packet of Marlboro cigarettes on the dashboard, where he had left it at

lunchtime ...

And remembered the lump in the carpet ... And realised what the lump was ... And remembered the hammering ... And began to feel rather sick ...

Unit 8

A Tree Project Helps the Genes of Champions Live On

As an eagle wheels overhead against a crystalline blue sky, Martin Flanagan walks

toward a grove of towering cottonwood trees beside the Yellowstone River, which is the color of chocolate milk due to the spring rain.

As Mr. Flanagan leaves the glaring sun of the prairie and enters the shady grove, his

eyes search for a specific tree. As he reaches a narrow-leaf cottonwood, a towering giant, he cranes his neck to look at the top. \says, petting the bark with his hand. \

When Europeans first came to North America, one of the largest primeval forests in the

world covered much of the continent. Experts say a squirrel could have traveled from the Atlantic coast to the Mississippi River without touching the ground. But only about 3 percent of America 's native old-growth forest remains, and many of the trees they hold are those that were not big enough to attract a logger 's eye. The result is a generation of trees that barely resemble the native forests that once covered the country.

攀登英语网 http://www.5pds.com 提供 That makes some scientists suspect that the surviving forests have lost much of their

genetic quality, the molecular muscle that made them dominate the landscape. When the loggers swept through, these scientists say, only poor specimens were left to reproduce. Other researchers wonder whether environmental factors or just plain luck may explain a good part of the supertrees' success.

To answer those questions, the mightiest trees of their types, or genetically identical

offspring, must be preserved for study, and that is what is being done by a handful of enthusiasts, including Mr. Flanagan and David Milarch, a nurseryman from Copemish, Mich. They are searching out the largest tree of each species and taking cuttings of new growth to make copies of genetic clones of the giants. With tissue culture and grafting, they have reproduced 52 of the 827 living giants and are planting the offspring in what they call \20,000 offspring have been planted.

The work is part of the Champion Tree Project, which began in 1996 with financial

help from the National Tree Trust, a nonprofit group in Washington.

\

Champion Tree Project, said.

State and federal agencies and private organizations have been keeping track of the

largest trees in each state for some time. The largest effort is the National Register of Big Trees, run by American Forests, a 125-year-old nonprofit group based in Washington. But the Champion Tree Project takes things a step further by making it possible for the largest trees to live on.

Eventually the Champion Tree Project hopes to reproduce enough genetically superior

trees for a nationwide reforestation project. The offspring of the native trees, should they prove genetically superior, could be especially valuable in urban settings, where the average tree lives just 7 to 10 years. But things like soil conditions, moisture and other environmental factors can also affect the success of the trees. Cloning

Cloning now is all over the news with identical sheep (as if they don't look enough

alike already) and tomatoes that stay fresh on the shelves for a longer time. The words \and \they have an overlapping meaning that becomes clear when we look through history.

Genetic engineering, in its broadest definition, means to manipulate a species so that a

particular trait is increased in the population. A trait is how an organism looks or acts or what it does. Brown eyes is a trait. Flying in circles is a trait. Climbing trees is a trait.

The earliest forms of genetic engineering occurred on farms, where most people on

earth lived at the time. They managed to do this by selecting seeds from plants that maybe had more fruit production or tastier leaves than other plants of its type.

攀登英语网 http://www.5pds.com 提供 They planted those seeds and grew plants that had more of the favorable traits. Then

they chose to save the seeds from the best of that lot to sow the next year. So, year by year, the farmers produced better and better crops. This type of activity probably has been going on since mankind first settled in villages and began making a life for themselves in one location, about 12,000 years ago!

The same sort of thing would have also happened with animals. By eating the animals

that didn't have favorable traits, like pulling a large load, and letting the animals with the favorable traits reproduce, herds and flocks would slowly develop more and more traits that humans found useful. It was thousands of years before mankind figured out how plants and animals reproduce themselves. With this knowledge, people could pollinate plants by hand or keep a pair of animals together in order to deliberately cause an increase in a favorable trait. It was only in the last 250 years that scientists began figuring out about chromosomes

and genes and the role they play in the way one generation passes its traits on to the next. And it's only been in the last 30 years that scientists have been able to cut out specific genes from one organism and put them in another.

It is this 30-year-old technology that is described by the narrow definition of genetic

engineering. Mankind has long been able to have a deliberate impact on the world around him. He now possesses the tools to deliberately impact himself. Some people are afraid of what might be done with that power.

The word \was first used as a noun to describe a population of cells that

reproduced themselves faithfully. A clone produces cells that not only have the same chromosomes, but which turn on the same genes, turn off the same genes, and therefore look identical, act the same, and do the same things.

If you took one bacterium and gave it food, it would reproduce itself until the food ran

out. The bacteria produced would all be identical and form what is called a clone or a \ With plants and animals this process is more difficult because of the many, many types

of cells that compose these organisms. Most of the cells do reproduce themselves very slowly, if at all, in an adult. Cancer cells are an exception to this, reproducing themselves rapidly. Cancer cells are natural clones and were the first human cells isolated and grown in laboratories. All the cells of a cell line produce cells which look identical and act the same way and do the same things.

The word \

either lines of identical looking and acting cells or genetically identical animals or plants. When we speak of cloned animals, we do not expect them to act alike; just have identical genes. Twins are nature 's clones, and we know they do not act alike or have the same personality at all.

Engineers Ask Nature for Design Advice

What does a flower known as the sacred white lotus have to do with house paint? In the

world of biomimicry, everything.

攀登英语网 http://www.5pds.com 提供 The white lotus is a symbol of purity, yet it grows in swamps around the world. The

secret of how the flower rises above its dismal environment was discovered by a German botanist, Dr. Wilhelm Barthlott at the University of Bonn, who spent 20 years studying the microscopic architecture of thousands of plant surfaces with a scanning electron microscope. Dr. Barthlott noticed that the leaves that needed the least amount of cleaning before they were scanned had the roughest surfaces.

And the cleanest leaf of all, the white lotus, turned out to have tiny points on it, like a

bed of nails, Dr. Barthlott found. When a speck of dust or dirt falls on the leaf, it shakes unsteadily on those points. When a drop of water rolls across the tiny points, it picks up the poorly attached dirt and carries it away.

The lotus, in other words, has a self-cleaning leaf.

The lotus effect, as it is called, has been applied to a house paint made in Germany

called Lotusan. The paint, on the market in Europe and Asia, is guaranteed to stay clean for five years without detergents or sandblasting. Now the lotus effect is being developed for other products, including roof shingles and auto paint.

The lotus effect is an example of biomimicry, an engineering approach that has been

gaining momentum in recent years as manufacturers look to nature to solve some engineering problems. By looking at the way plants and animals handle similar kinds of problems, the engineers hope to make products that are less polluting, use fewer materials and even cut costs. \

who wrote \published in 1997, and is now a consultant on the subject. \should find a way to create conditions favorable to life, not toxic to life.\

Nature has inspired engineers for a long time, for things like hypodermic needle tips

shaped like rattlesnake fangs. But the search for biological designs with commercial potential has become more sophisticated and more widespread.

The examples are many. Dr. Robert J. Full, a biologist at the University of California at

Berkeley, has discovered that the attractive force between molecules allows the gecko, a small lizard, to scamper across ceilings and up walls at three feet per second.

Microscopic tips of hair on the gecko 's feet actually get close enough to interact with

the molecules of the surface it is crossing. To take another step, the gecko peels each foot from the wall. The charge is so powerful that, theoretically, a 90-pound weight could be suspended from a gecko.

A novel approach to hearing comes from the parasitic Ormia fly, which is being studied

at the State University of New York at Binghamton and at Cornell. Crickets, able to disguise their location by how they chirp, cannot fool the Ormia, which lays its eggs on the cricket and has an ear that has evolved to find them. Researchers have discovered that the fly has the biological equivalent of directional microphones in its ears; they hope that their studies will lead to a better hearing aid for people.

攀登英语网 http://www.5pds.com 提供 Flowers in the Desert?

Recognized as the largest desert in the world, the Sahara Desert extends across North

Africa, covering over 3 million square miles from the Atlantic Coast to the Nile River Valley. Except for an occasional oasis, this vast and barren landscape consists mainly of sand dunes, stone plateaus, surface gravel, and eroded mountains. The intense sun causes daytime temperatures to rise above 135 degrees Fahrenheit in the shade, and droughts commonly last for years. However, scientists are trying to restore the Sahara so that it can sustain life as it did many years ago.

Desert Life Long Ago

Paintings found on the walls of caves in the Sahara Desert suggest that a few thousand

years ago lush vegetation thrived and covered the desert floor. Many curious and unusual insects, reptiles, birds, and other animals had access to food sources that allowed them to grow and reproduce. At that time, huge river systems and many oases supported growing and flourishing communities where many people lived.

Destruction of a Land

Research scientists believe that the land became a desert for three reasons. For centuries,

wilderness tribes have wandered from place to place in search of food, water, and grazing land for their herds of animals. These nomadic people have always considered the number of animals they have as a sign of wealth. It is considered more important to have 100 sick and starving animals than 15 healthy ones. The large herds have been allowed to roam freely and graze on desert plants and grass. Over time, enormous sections of land have been left exposed, causing soil erosion. Today, the Sahara Desert is expanding southward as these wandering tribes continue to allow their animals to overgraze.

In addition to allowing overgrazing, these people cut down whatever trees they could

find and used them for firewood. The sand is unable to hold on to the intense heat of the day, so nighttime temperatures often drop below freezing. Looking for warmth, the wilderness tribes stripped the desert of whatever hardy shrubs and stunted trees did grow.

As tribesmen and animals slowly consumed and destroyed the vegetation, nothing was

left to hold the soil together and protect it from erosion. Wind and rain carried away precious elements, such as nitrogen, that could keep the soil fertile.

Desert Restoration

Scientists have been exploring different ways to revive and restore the Sahara Desert.

Through research and experiments, they hope to be able to produce vegetation that will once again support an abundance of life.

Huge aquifers filled with large quantities of rainwater lie under much of the desert

surface. Scientists believe this rainwater simply filtered down through the sand over hundreds of years and collected in these giant, rocky holding tanks. By harnessing the sun 's power, scientists in the Sahara have conducted experiments in which they generated huge amounts of electricity. This electricity was then used to operate drilling machines and pumps to pull the rainwater up from the aquifers. By drilling a hole one mile deep into the floor of the desert, one machine was able to recover more than 80 gallons of ice-cold water each second, or 288,000 gallons per hour.

攀登英语网 http://www.5pds.com 提供 Scientists have had some success turning this barren wasteland into useful farmland.

Today the desert is dotted with huge wheat fields irrigated by an elaborate system of pipes that carry water from the underground aquifer. Farmers have also learned that plants grow better if seeds are planted next to stones. Studies suggest that stones provide protection from the sun, allowing seeds to grow in a shady and cool environment.

Science is helping to restore the desert in other ways. Greenhouses have been built to

protect plants from the sun and provide enough humidity so that less water is needed for irrigation. Another idea involves growing plants that can live on a diet of salt water, since the ocean is so close to the desert. Finally, scientists are experimenting with different ways to return life-supporting nitrogen to the soil.

The results of the desert experiments have been promising. Scientists hope that the

Sahara will one day flourish with the plant life and flowers that bloomed there thousands of years ago.

本文来源：https://www.bwwdw.com/article/4kjw.html