For many years, humans have tried to find the secret to staying young. Although it has yet to be discovered, we may be closer than ever to finding a way that can slow down the aging process. A recent study by researchers from Duke L Jniversity in the US found that cutting one sdaily intake of calories could slow down biological aging, which means you might be able to hang on to your youthful looks a little longer. Previous research has shown that calorie restrictions slow aging in worms, flies and mice. So researchers wondered if it could have the same effect on people.To find out, Daniel Belsky and her teamTo find out, Daniel Belsky and her team examined data from a study by the National Institute on Aging, based in the US, which involved 220 people. During the two-year study, 145 people in the restriction group cut their calorie intake by 25 percent. Meanwhile, 75 peoplein the control group maintained their normal diets.At the start of the study, the two groups had no difference inbiological age.The average participant was 38 years old, with a biological age of 37. However, after each 12- month period, participants in the restriction group saw an increase in biological age by an average of 0.1 1years. Meanwhile, those in the control group saw a rise by an average of 0.71 years. The researchers believe the difference between these groups shows that cutting calories does slow biological aging. Although they didn't explain the reason behind this, researchers at Brigham Young University in the US provided an explanation after they carried out a similar study on mice. Theybelieve fewer Calories slow down a mechanism in cells called the ribosome (核糖体)，at least in mice. The mechanism is responsible for making vital proteins in cells,but with fewer calories it slows down, giving it more time to repair itself, The ribosome is complex like a car, and itneeds to replace the parts that wearout the fastest from time to time, according to John Price, a biochemistry professor at Brigham Young University.“When tires wear out, you don't throw the whole car away and buy new ones. It's easier to replace the tires," Price told VOA. But this doesn't mean that people who want to look younger should start skipping meals, especially given the study's early stage. Proper nutrition is important, Price explained. “Food isn't just material to be burned -it's a signal that tells our body and cells how to respond,"he told Science Daily.The purpose of the research was ().A.test the influence of calorie restrictions on aging.B.explain why people have to maintain a normal diet.C.find the most efficient way to control calorie intake.D.invent technology that keeps people young and healthy.Which of the following statements is TRUE about the experiment ()?A.The biological age of people in the control group increased more than those in the restriction group.B.Some participants were asked to double the amount of food they ate.C.Flies and mice were used to compare the results of the human test with.D.AlI the participants were of the same biological age at the start.According to John Price, ().A.a higher level of calorie intake meansmore healthy proteins.B.reducing calorie intake could allow the ribosome to repair itself better.C.the fewer calories one takes in, the better the ribosome works.D.the ribosome is an important cell that controls the aging process.

第1题

was designed many years ago，with a goal in mind：transmitting the human voice in a more

-or-less recognizable form．

A．DWDM

B．PSTN

C．internet

D．WLAN

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第2题

完形填空Many of the world’s pollution problems have been caused by the crowding of lar

ge groups of people into cities.Satisfying the 21 of the people leads to further polluting by industry.If the rapid increase in human population 22 at the present rate (比率), there may be much greater harm.Some scientists speak of the 23 in number of people as “Population Pollution”.

About 2000 years ago, the world 24 was probably about 250 million.It reached a billion in 1850.By 1930 the population was two billion.It is 25 three and a half billion.It is expected to double by the year 2000.If the population continues to grow at the same 26 , there would be 25 billion people in the world a hundred years from now.

Man has been using the earth’s 27 more and more rapidly over the years.Some of them are almost gone.Now many people believe that man’s greatest 28 is how to control the growth of this population.The materials in the world will not support the human population in time to come if the present rate of increase continues.29 there is over crowding in the cities and hunger in some countries.Can man’s rate of increase continue？

Many people believe that human survival (幸存者) in the future 30 on the answer to the question.

21.A.needs

B.supplies

C.service

D.supports

22.A.stops

B.continues

C.slows down

D.adds to

23.A.increase

B.reduce

C.country

D.improvement

24.A.people

B.situation

C.population

D.land

25.A.now

B.in the past

C.in the future

D.then

26.A.place

B.time

C.rate

D.result

27.A coal

B.oil

C.mines

D.resources

28.A.problem

B.power

C.plan

D.idea

29.A.Already

B.Yet

C.Still

D.Often

30.A.feeds

B.lives

C.keeps

D.depends

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第3题

Many Native Americans closely resemble Asians. This has led most scientists to （1) believe somet

Many Native Americans closely resemble Asians. This has led most scientists to(1)believe something about Native Americans. They think that most Native Americans(2)from a distant group of people. These people(3)from Siberia across the Bering Strait, between 17,000-11,000 years ago. The exact time and 4 is still under question. That is, it is still a(n)(5)of debate. The time they traveled and the route they took is still being argued, as is whether it happened(6).

(7)recently, some anthropologists (人类学家) argued that the migration occurred 12,000 years ago. However, there are a number of difficulties with this theory —(8)particular, the presence of people in the Americas earlier than one might think. There is growing evidence of human(9)in Brazil and Chile 11,500 years ago or earlier. There is also(10)of humans living in the Americas some 50,000 years ago.(11), other possibilities have been suggested.

They may have(12)the land bridge several thousand years earlier or they may have sailed along the western coast. However, some(13)this theory. They think that humans(14)skills for sailing during that era.

Some consider the genetic and cultural evidence for an Asian origin overwhelming. It should be noted,(15), that some other people are very upset at this idea. Many present-day Native Americans(16)the above theories. They say those who put forward such theories have political(17)They have their own traditional stories that offer(18)of where they came from. Their own stories claim that their(19)are different from what scientists say. Those accounts, though, have mostly been(20)by scholars. Therefore, the origin of Americans still remains a mystery to be explored.

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第4题

Who designed the first helicopter? Who(1)one of the most famous pictures in th

e world? Who knew more about the human body than most(2)? There is an answer

(3)all these questions - Leonardo de Vinci (达芬奇),Leonardo may have been the greatest genius(4)have ever known. He lived in Italy around the year 1500, but many of his inventions seem modern to us today. For example, one of his notebooks has drawings of a helicopter. Of course, he couldn' t(5)a helicopter with the things he had. But scientists say his idea would have worked. But Leonardo(6)an inventor. He was one of the greatest a rtists of his day. By the time he was twenty years old, he was called a master painter, and as he got older he became(7)more famous. Sometimes he drew a hand ten different ways(8)he was ready to paint.Many of Leonardo' s wonderful paintings are still with(9) today. You may know one of his most famous works the(10)woman known as theMona Lisa.

1.A. took

B.made

C.painted

D.invented

2.A.artists

B.doctors

C.painters

D.people

3.A.to

B.of

C.for

D.from

4.A.the scientists

B.the artists

C.the world

D.people

5.A.draw

B.paint

C.work

D.build

6.A.was just

B.wasn't just

C.wasn't

D.was no longe

7.A.less

B.no

C.even

D.very

8.A.before

B.after

C.because

D.when

9.A.him

B.us

C.them

D.you

10.A.interesting

B.crying

C.smiling

D.surprising

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第5题

For about three centuries we have been doing science, trying science out, using science fo

r the construction of what we call modern civilization. Every dispensable item of contemporary technology, from canal locks to dial telephones to penicillin, was pieced together from the analysis of data provided by one or another series of scientific experiments. Three hundred years seems a long time for testing a new approach to human interaction, long enough to settle back for critical appraisal of the scientific method, maybe even long enough to vote on whether to go on with it or not. There is an argument.

Voices have been raised in protest since the beginning, rising in pitch and violence in the nineteenth century during the early stages of the industrial revolution, summoning urgent crowds into the streets any day on the issue of nuclear energy. The principal discoveries in this century, all in all, are the glimpses of the depth of our ignorance about nature. Things that used to seem clear and rational, matters of absolute certainty—Newtonian mechanics, for example—have slipped through our fingers, and we are left with a new set of gigantic puzzles, cosmic uncertainties, ambiguities; some of the laws of physics are amended every few years, some are canceled outright, some undergo revised versions of legislative intent as if they were acts of Congress.

Just thirty years ago we call it a biological revolution when the fantastic geometry of the DNA molecule was exposed to public view and the linear language of genetics was decoded. For a while, things seemed simple and clear, the cell was a neat little machine, a mechanical device ready for taking to pieces and reassembling, like a tiny watch. But just in the last few years it has become almost unbelievably complex, filled with strange parts whose functions are beyond today's imagining.

It is not just that there is more to do; there is everything to do. What lies ahead, or what can lie ahead if the efforts in basic research are continued, is much more than the conquest of human disease or the improvement of agricultural technology or the cultivation of nutrients in the sea. As we learn more about fundamental processes of living things in general we will learn more about ourselves.

What CAN'T be inferred from the 1st paragraph？

A．Scientific experiments in the past three hundred years have produced many valuable items.

B．For three hundred years there have been people holding hostile attitude toward science.

C．For centuries scientific discoveries have been hailed by the human world unanimously.

D．Three hundred years is not long enough to settle back for critical appraisal of the scientific method.

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第6题

Why do Westerners love their pets so much, almost as if they were their children? I su

Why do Westerners love their pets so much, almost as if they were their children？ I suppose one reason is that for more than one hundred years many children's books in England and in America were animal stories.By this we mean stories that gave the animals human names, human voices, human emotions, and even faces that look almost human.Many of these stories taught a moral lesson, like honesty or kindness or hard work.My mother read animal stories to me as a child, and my wife and I read some of the same animal stories to my boys when they were small, and now they read animal stories to their children.Some are the same stories about dogs and cats and rabbits and horses.So children in America grow up with good feelings toward animals. Many families would like to have a purebred dog or cat, that is an animal whose parents come from a single kind of animal.But purebred animals are expensive.And those that are registered with a special dog or cat club are even more expensive since there is a written record of their ancestors for many generations.What often happens is that a family's first pet will come from some friend whose pet has had babies.Or they may get a pet from an animal shelter.Every city and many smaller towns have a humane society which cares for animals that are found and for animals which people no longer want.They try to find the owner of lost pets and to find homes for the others.Over the years my wife and I and our children have gotten some very nice dogs for our family from animal shelters, usually at no cost.

But some families do not want a house dog or a house cat.They want an outside dog or cat.So the animal stays outsides the house most of the time.Special dog houses are made for such dogs to use, especially at night in the colder parts of North America.

1.Why do Western people love their pets so much？ ()

A.Because their children don't have many friends.

B.Because they have leisure time and enough money.

C.Because they are influenced by animal stories.

D.Because they regard pets as their children.

2.Since they have heard a lot of animal stories, American children tend to () .

A.love animals when they grow up

B.treat animals rudely

C.live with animals

D.dislike animals

3.A purebred dog refers to a dog()

A.which is brought up by one family

B.whose parents come from the same area

C.whose parents belong to the single kind of dog

D.which is bred in a pure house

4.How do most Americans get their first pet？ ()

A.They buy it from a pet shop

B.They pick up one from the street

C.They always get one from the animal shelter

D.They get it from their friends

5.Not all pets stay with their masters in the house all the time for().

A.it's good for them to stay outside

B.people think they are dirty

C.Some people don't want a house dog or a house cat

D.they don't like to stay in their masters' house

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第7题

ecu什么意思

根据所给10个英语单句的意思，从所给的15个词汇中挑选出10个合适的词或短语分别给每个句子填空。

artists	injured	active	attach	came into being
teenagers	hopeless	shortcoming	generous	in search of
fluent	selfless	goal	inspect	concerned about

The design of the room was in the fancy style popular in those days, and it was also a treasure decorated with gold and jewels, which took the country’s best ________ about ten years to make.

Many kings and princes wanted to marry Atlanta, but when they heard of her rules they knew it was ________.

Anyhow, my ________ is to provide humans with a life of high quality, and I am now truly filled with happiness that I am a devoted friend and helper of the human race.

Dinosaurs lived on the earth tens of millions of years ago, long before humans ________ and their future seemed secure at that time.

Many young people often dream of playing in front of thousands of people at a concert, and, to be honest, a lot of them ________ great importance to becoming rich and famous.

If your friend comes to school very upset, tell him that you are ________ him and you will meet after class and talk then.

India has a very large number of ________ English speakers because Britain ruled India from 1765 to 1947, and English became the language for government and education.

I am fond of my sister Wang Wei but she has one serious ________ — she can be really stubborn.

On July 28, 1976, the city of Tangshan in Hebei Province was hit by a terrible earthquake and the number of people who were killed or seriously ________ reached more than 400,000.

It was in 1952 that Elias went to Mandela for legal advice, and Mandela was ________ with his time, for which Elias was very grateful.

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第8题

False teeth have been found in Italy in human heads that are over 2,500 years old

False teeth have been found in Italy in human heads that are over 2,500 years old. They were made of bone and set in gold. However，for hundreds of years afterwards，the apparent dental skill of those early people was lost. Without false teeth people looked old before their time，since so many lost their teeth at an early age.

Toward the end of the 17th century，rich people could buy false teeth made from ivory. The teeth were tied together with silk thread，but it was difficult to keep them in the mouth. That was why rich people would rather buy teeth from the poor who would often sell their teeth to buy food and clothing.

Early in the 18th century a French doctor used steel springs to hold teeth in place. However，it was difficult to close one‘s mouth! Late in the same century porcelain (瓷)teeth set in gold were often used to make false teeth.

Although the use of artificial teeth increased，human teeth continued to be used also. In the 19th century，teeth from soldiers killed in battle were made into artificial teeth. For example，teeth from the dead in the American Civil War were sent to England.

By the middle of the 19th century，an American doctor，Claudius Ash，invented a better kind of porcelain tooth made of a special kind of hard rubber.

26.When did people with the earliest false teeth live according to the passage？

[A] At the end of the 17th century.

[B] In the early 18th century.

[C] In the middle of the 19th century.

[D] Over 2,500 years ago.

27.Which material would wealthy people use to make artificial teeth in 1693？

[A] Porcelain.

[B] Hard rubber.

[C] Ivory.

[D] Bone.

28.Who first used steel springs to tie false teeth together according to the passage？

[A] An Italian doctor.

[B] A French doctor.

[C] An American doctor.

[D] An English doctor.

29.We can learn from the passage that ___________.

[A] one looked older than his real age with artificial teeth

[B] we are using the same method as ancient people in making false teeth

[C] poor people would often sell their teeth to get money in the 17th century

[D] human teeth were no longer used in making false teeth after the 18th century

30.The passage is mainly about ___________.

[A] the discovery of false teeth

[B] the material of false teeth

[C] the use of false teeth

[D] the history of false teeth Passage Three

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第9题

The most fundamental group to which a person belongs is the family. The institution of the family exists in almost every

The most fundamental group to which a person belongs is the family. The institution of the family exists in almost every human culture. It is considered by behavioral scientists to be one of the oldest institutions in human history.

The family unit serves many important functions. The performance of these functions is he reason for the family's importance. Above all , the family serves as a mechanism of species survival (生存，幸存) .

Families also have important economic functions. In primitive societies, the tasks of gathering food and providing shelter were divided among family members. Today, both husband and wife may work and share the duties of homemaking and child rearing.

In addition to its survival and economic functions, the family gives its members social status. In many societies, a person is not considered a complete member until he has married and produced children. Finally, the family helps to meet the basic emotional needs of a person through the love and support received from parents, siblings (兄弟姐妹)， and relatives.

21. Which of the following best states the main idea of the passage？ ____________.

A. The family has changed greatly over time

B. Many of the functions of the family today are being performed by government agencles

C. The most important role for the family is to gather food

D. The family has served many useful functions throughout history

22. According to the passage, which of the following is an example of the role of the family in giving status？____________.

A. A child is taught to respect his elders

B. A couple work for several years to save for the purchase of a home

C. A politician makes a campaign commercial with his family

D. A mother comforts a child after he skins his knees

23. It can be concluded from the passage that the family is ____________.

A. undergoing many changes

B. the only useful social institution

C. likely to exist in future societies

D. not the same today as it was in the past

24. As it is used in the second paragraph of the passage, the word "mechanism" means ____________.

A. parts of an organism or system which work together

B. racial group united by language, religion, custom, etc.

C. the people living in one place, district or country, considered as a whole

D. a worker skilled in using or repairing machines or tools

25. Based on the information in the passage, you can infer that the passage is 一一一一一一·

A. about the family's mechanism of species survival

B. about the social, economic, and emotional usefulness of family throughout human history

C. about duties of the family shared by both husband and wife

D. about the emotional needs received from parents, siblings, and relations

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第10题

Recently some American scientists have given a useful sincere piece of advice to peopl

e in industrialized nations that they would be much healthier if they ate more of the same kind of food eaten by humans living more than 10,000 years ago.

The scientists say that the human body has changed very little since human first appeared on the earth, but the way we live has changed greatly.Our body has not been able to deal with these changes in life style. (方式) and this has led to new kinds of sicknesses.These new sicknesses were not known in ancient times (古代).So they are called “diseases of civilization”.Many cancers and diseases of the blood system (系统),including heart attacks and stroke (中风) are examples of such diseases.

Scientists noted that people in both the Old Stone Age and the New Stone Age enjoyed very little alcohol (酒精) or tobacco (烟草),probably none.Ancient people also got a great deal of physical exercise, but a change in food is one of the main differences between life in ancient times and that of today.

Stone-age people hunted wild animals for their meat, which had much less fat than domestic or tame ones (家畜).They also ate a lot of fresh wild vegetables and fruits.They did not have milk or any other dairy products, and they made very little use of grains.But today, we eat a large amount of these.We eat six times more salt than our remote ancestors.We eat more sugar.We eat twice as much fat but only one third as much protein (蛋白质) and much less vitamin.(维生素) C.

People today probably do not want to live the way people thousands of years ago did, but scientists say that we would be much healthier if we ate much the same way our remote ancestors did ,cutting the amount of fatty, salty and sweet food.

1.According to the passage, people in industrialized nations would be much healthier if they eat()

A.more food as human living 10,000 years ago did

B.as human living 10,000 years ago ate

C.more kinds of food eaten by people living over 10,000 years ago

D.more of the same kind of food eaten by people over 10,000 years ago

2.New kinds of sicknesses have been found because().

A.the human body has changed compared with(同……比较) human first appeared on the earth

B.the way we live has changed a little

C.our body can't deal with the changes in life style

D.the way we live today is proper for the human body

3.What is the main cause that people suffer from a lot of new sicknesses？ ()

A.Ancient people did a great deal of physical exercise

B.People today have a lot of alcohol

C.People today have more tobacco

D.Food today is quite different from that of ancient times

4.Which of the following belongs to the dairy product？()

A.Milk

B.Corn

C.Pork

D.Flour

5.According to some scientists, Stone-age people were much healthier than people today because they ate a lot of ______.

A.milk and other dairy products

B.wild animals, fresh.wild vegetables and fruits

C.salt and sugar

D.grain foods

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第11题

1：第一篇Reading Comprehension: When global warming finally came, it stuck with a vengeanc

e. In some regions, temperatures rose several degrees in less than a century. Sea levels shot up nearly 400 feet, flooding coastal settlements and forcing people to migrate inland. Deserts spread throughout the world as vegetation shifted drastically in North America, Europe and Asia. After driving many of the animals around them to near extinction, people were forced to abandon their old way of life for a radically new survival strategy that resulted in widespread starvation and disease. The adaptation was farming: the global-warming crisis that gave rise to it happened more than 10,000 years ago. As environmentalists convene in Rio de Janeiro this week to ponder the global climate of the future, earth scientists are in the midst of a revolution in understanding how climate has changed in the past—and how those changes have transformed human existence. Researchers have begun to piece together an illuminating picture of the powerful geological and astronomical forces that have combined to change the planet's environment from hot to cold, wet to dry and back again over a time period stretching back hundreds of millions of years. Most important, scientists are beginning to realize that the climatic changes have had a major impact on the evolution of the human species. New research now suggests that climate shifts have played a key role in nearly every significant turning point in human evolution: from the dawn of primates some 65 million years ago to human ancestors rising up to walk on two legs, from the huge expansion of the human brain to the rise of agriculture. Indeed, the human history has not been merely touched by global climate change, some scientists argue, it has in some instances been driven by it. The new research has profound implications for the environmental summit in Rio. Among other things, the findings demonstrate that dramatic climate change is nothing new for planet Earth. The benign global environment that has existed over the past 10,000 years—during which agriculture, writing, cities and most other features of civilization appeared—is a mere bright spot in a much larger pattern of widely varying climate over the ages. In fact, the pattern of climate change in the past reveals that Earth's climate will almost certainly go through dramatic changes in the future—even without the influence of human activity, 1.The message the author wishes to convey in the passage is that ______.

A.human civilization remains gorious though it is affected by climatic changes

B.mankind is virtually helpless in the face of the dramatic changes of climate

C.man has to limit his activities to slow down the global warming process

D.human civilization will continue to develop in spite of the changes of nature

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