大学四级-1874及答案解析.doc

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1、大学四级-1874 及答案解析(总分：710.00，做题时间：90 分钟)一、Part Writing(总题数：1，分数：106.50)1.Directions: For this part, you are allowed 30 minutes to write a short essay comparing the income sources between Chinese and American college students. You should write at least 120 words based on the information provided by the

2、following chart.Income Sources between Chinese and American College Students（分数：106.50）_二、Part Listening Com(总题数：0，分数：0.00)三、Section A(总题数：4，分数：106.50)(1).A. If John is lucky enough, he might get a scholarship.B. There is no way for John to win a scholarship.C. John has to wait for a good chance to

3、get a scholarship.D. John doesnt want to go to Cambridge.（分数：7.10）A.B.C.D.(2).A. Some people would rather buy supplies at school.B. Supplies arent always available at the bookstore.C. The bookstore is very close to class.D. The bookstore isnt always that full.（分数：7.10）A.B.C.D.(3).A. At a science exh

4、ibit.B. At a department store.C. Near an art museum.D. Near a paint store.（分数：7.10）A.B.C.D.(4).A. 8:45 B. 9:25 C. 9:05 D. 9:10（分数：7.10）A.B.C.D.(5).A. Go to see a film.B. Study harder in order to catch up with other classmates.C. Do some exercise to get some fresh air.D. Try her best to finish the sc

5、hoolwork at home.（分数：7.10）A.B.C.D.(1).A. To make an appointment.B. To look after her son.C. To meet an old friend.D. To see a doctor.（分数：7.10）A.B.C.D.(2).A. A clerk at the airport.B. A policewoman.C. A clerk at the railway station.D. A taxi-driver.（分数：7.10）A.B.C.D.(3).A. Professor Lis course has bee

6、n cancelled.B. Professor Lis course was already full.C. Professor Lis course was almost over.D. The college had closed.（分数：7.10）A.B.C.D.(1).A. Have enough working experience.B. Read enough sketch books.C. Attend the afternoon meeting.D. Enroll in another class.（分数：7.10）A.B.C.D.(2).A. A textbook.B. S

7、ome drawings.C. A bouquet of flowers.D. Her homework.（分数：7.10）A.B.C.D.(3).A. Confused.B. Surprised.C. Encouraged.D. Annoyed.（分数：7.10）A.B.C.D.(1).A. They didnt have a credit card.B. They both felt sick.C. They grew tired of waiting.D. They were afraid that the concert had been cancelled.（分数：7.10）A.B.

8、C.D.(2).A. Shes uncertain about the change in plans.B. Shes worried about the ticket sellers.C. Shes pleased about he mans purchase.D. Shes impatient with the delay of plans.（分数：7.10）A.B.C.D.(3).A. By charging them to their personal account.B. By using a credit card.C. By writing a personal check.D.

9、 By paying in cash.（分数：7.10）A.B.C.D.(4).A. Stay where he is.B. Return after lunch.C. Try to get the tickets elsewhere.D. Go home to telephone the order.（分数：7.10）A.B.C.D.四、Section B(总题数：0，分数：0.00)五、Passage One(总题数：1，分数：21.30)(1).A. The advantages of X-rays over thermographs.B. The advantages of scien

10、tific photography for diagnostic purposes.C. How thermograph photography was invented.D. Several new techniques for reducing pain.（分数：7.10）A.B.C.D.(2).A. With different colors.B. With a thermometer.C. With charts and graphs.D. With moving lights.（分数：7.10）A.B.C.D.(3).A. To discover the side effects o

11、f thermographs.B. To improve the analysis of blood and tissue samples.C. To find out why a body requires rest.D. To get a better understanding of illness.（分数：7.10）A.B.C.D.六、Passage Two(总题数：1，分数：21.30)(1).A. In the white pages. B. In the yellow pages.C. In the blue pages. D. In a special section.（分数：

12、7.10）A.B.C.D.(2).A. At the end of the telephone book.B. In the front of the white pages.C. On the first page of the telephone book.D. Right after the white pages.（分数：7.10）A.B.C.D.(3).A. Tell the operator what has happened.B. Ask the operator to put you through.C. Check the phone number and call agai

13、n.D. Ask the operator whats wrong.（分数：7.10）A.B.C.D.七、Passage Three(总题数：1，分数：28.40)(1).A. Acting is a very hard work.B. Acting as a career is too short.C. The courses at the drama school lasts too long.D. There are already too many actors.（分数：7.10）A.B.C.D.(2).A. Because they need to work day and nigh

14、t.B. Because they have to do all kinds of stage work.C. Because they have no opportunity:D. Because they cant learn anything.（分数：7.10）A.B.C.D.(3).A. They dont care whether their job is hard or not.B. They are easily satisfied.C. They like the stage naturally.D. They can meet a lot of famous persons

15、there.（分数：7.10）A.B.C.D.(4).A. Such kind of case happened immediately.B. Such kind of case happened slowly.C. Such kind of things rarely happened.D. Such kind of things always happened but unexpectedly.（分数：7.10）A.B.C.D.八、Section C(总题数：1，分数：71.00)Global warming is the most serious problem humanity has

16、 ever faced, Theres more hype (宣传) on this (26) than any other. In the late 1970s computer models predicted that because of the heat-trapping buildup of carbon dioxide in the (27) , the earth would warm up by several degrees over the next century. A lot of bad weather gets linked to global warming:

17、in the media, which regularly predict that more and (28) hurricanes, longer (29) and more (30) rainstorms will result.What has actually been going on? One computer model says the earths temperature should have already increased by an easily (31) 0.3 to 0.4 degrees Celsius since 1979. Some (32) , how

18、ever, show that the earths temperature has actually cooled slightly over the last 18 years. And despite (33) , the frequency of intense Atlantic hurricanes and their (34) have not increased over the past half-century. If climate models turn out to be correct, it may be prudent to limit carbon-dioxid

19、e (35) in the future. But many experts feel there is no need to rush into extreme action.（分数：71.00）填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_九、Part Reading Compr(总题数：0，分数：0.00)十、Section A(总题数：1，分数：35.50)This book is about the future of technology. In it we will examine so

20、me of the many recent developments in a few key fields and try, in a (36) way, to predict where they will take us in the next fifteen years or so.If that sounds like a modest goal, its not. Technology is the (37) force of our time and probably of all time to come. It appears in more (38) than we can

21、 count. It changes so rapidly that no scientist or engineer can keep up with his own field, much less with technology in general. It has (39) and shaped our lives at every turn, we live in technology as fish live in the sea, and we have only a little better chance of (40) the details of its future c

22、hanges.Yet the task is well worth undertaking. Whatever hints we can gather about the future will help us prepare for the changes to come. And though technology has made the present much less (41) than the past, and surely will make the future more disturbed still, there is good reason to hope that

23、our lives, in sum and on average, will be better as a result. In an age of uncomfortable (42) , this is reassurance we all can use.For an idea of what is to comein magnitude if not in specificslook to the past. In the last ninety years, the world has shrunk, while human experience has (43) almost be

24、yond the recognition of those who grew up in our grandparents generation.A century after Americas founders (44) their agrarian (耕地的) democracy, nearly all their descendents still lived on farming. Since World War I, technology has (45) us from behind horse-drawn plows and plugged us into assembly li

25、nes and offices. Today it is removing many of us from offices and letting us work at home or forcing us to work on the road.A. similaritiesB. forecastingC. conceivedD. varietiesE. reformedF. stableG. challengesH. advancedI. neutralJ. permeatedK. opportunitiesL. limitedM. extractedN. remindingO. domi

26、nant（分数：35.50）填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_填空项 1:_十一、Section B(总题数：1，分数：71.00)Weight-Loss Nirvana?A In the U. S., where one in three adults is seriously overweight, the news carried by the journal Science last weekthat Friedman and his colleagues at the Howard Hughe

27、s Medical Institute and New York Citys Rockefeller University had discovered a magical dose that melts fat in a matter of weeksresonated with unusual force. Momentarily, at least, it encouraged the spirits of millions of lifelong dieters and boosted the stock of Amgen, the biotechnical firm based in

28、 California that holds the license on the underlying technology. It is too early to predict, however, whether this rare elixir (called leptin, after the Greek leptos, meaning slender) will be a stunning pharmaceutical (制药上的) success or just another “miracle“ cure that never pans out. Even if all goe

29、s well, it could be five to ten years before leptin is approved in the U. S. for human use. Researchers must first demonstrate that leptin benefits people as well as animals and that it causes no serious side effects.B The search for leptin began in the 1960s, when Douglas Coleman, a researcher at t

30、he Jackson Laboratory in Bar Harbor, Maine, began studying a strain of fat laboratory mice. In a series of creative experiments, Coleman surgically joined the blood vessels of an obese (肥胖的) mouse to those of a normal-size mouse, creating a sort of artificial Siamese twin. What happened then was ast

31、onishing: the fat animal immediately began to lose weight. This suggested that the blood of non-obese mice carried an effective biochemical messenger, one that played an important role in regulating appetite and metabolism (新陈代谢). But the mysterious agent was present in such minuscule quantities tha

32、t no one was able to isolate it.C Friedman picked up the challenge, applying new tools developed by the field of molecular genetics. The secret factor, he reasoned, must be produced by a gene that was defective in the obese mice. So he began to hunt for such a gene, the ob, or obese, gene. Sure enou

33、gh, late last year, after eight years of effort, Friedman and his colleagues pinpointed the ob gene in both average-weight and obese mice. They then inserted the normal gene into bacterial (细菌的) cells, providing at long last detectable quantities of the protein they called leptin.D By injecting lept

34、in into obese mice, three separate teams of researchers, including Friedmans, have confirmed that this protein is indeed the blood factor that makes fat mice thin. But they are still trying to puzzle out just how it works. Friedman, for one, believes leptin is almost certainly a hormone that travels

35、 through the bloodstream to act on the brain. In fact, it appears leptin may act in a feedback loop (反控循环) like the temperature sensor in a thermostat (恒温器)or in this case a “fatstat“to tell the body whether to turn metabolism and appetite up or down. Thus when leptin is low, hunger pangs increase,

36、body temperature drops, and metabolism slows. When leptin is high, everything reverses. In such fashion, the brain strives to keep body weight stable and fluctuations small.E Because leptin is produced in fat tissue (组织), the fatter an animal is, the more leptin its cells should make. Normal mice th

37、en respond to weight gain by turning out more leptin. As a result, their appetites slow down and their energy consumption speeds up. But the obese mice cannot produce leptin, so their brains never receive this vital message. “These animals,“ says Friedman, “get fat because they think theyre starving

38、, and then when we give them the protein, they get thin because they think theyre fat!“F What, if anything, does this have to do with people? Perhaps a good deal. For humans have an ob gene that is virtually the same as the mouse gene, and it is possible that at least some folks have trouble keeping

39、 off kilos because of mutation (突变) in this gene. Most experts, however, agree that defects in the ob gene are not likely to be a major reason for obesity in people. But that does not mean leptin might not be therapeutically (治疗学的) useful for many other overweight people. In last weeks Science, for

40、example, a team of researchers from the pharmaceutical company Hoffmann-LaRoche described how they fattened lean mice by giving them unrestricted access to high-fat food. Then they administered leptin. The mice responded by cutting their food intake and shedding the extra grams, suggesting leptin ma

41、y have value in reversing more typical cases of weight gain.G What about side effects? Injections of leptin do not, as one might fear, turn lean mice into starving wretches. After losing weight, researchers from Amgen reported, normal mice stabilize both their food intake and their metabolism. Obese

42、 mice likewise reach an ideal leanness, and then stop losing weight. The pattern of weight loss is also encouraging. For unlike extreme calorie restriction, which can weaken muscle, leptin appears to melt fat while leaving lean tissue untouched. On the basis of such data, Amgen (which paid Rockefell

43、er University $20 million for patent rights to make products based on the ob gene) has announced that it hopes to begin making human trials as early as next year.H Many experts find these plans too optimistic. Just because researchers have not noted worrisome side effects yet, critics say, does not

44、mean that none will emerge. Leptin, they point out, is a serious drug, not the easy-to-swallow “thin pill“ dieters have dreamed of for so long. To do its work, leptin would probably have to be either injected daily or implanted under the skin for life. In the laboratory experiments reported last wee

45、k, the obese mice started regaining weight as soon as the injections stopped. Even with a boost from something like leptin, cautions Dr. Ahmed Kissebah, an obesity expert at the Medical College of Wisconsin, the formerly fat cannot afford to become less alert. “People will still have to lose weight

46、the hard way,“ he predicts. “Itll be like diabetes: you still have to exercise and watch your food intake.“I Regardless of what eventually happens in the marketplace, the discovery of leptin is occasion for celebration. It has provided scientists with a new way for exploring a still poorly understoo

47、d metabolic pathway, one that probably consists of many other equally powerful compounds, each of which could lead to new drugs. To the millions of seriously overweight Americans, help with a frustrating conditionyears of guilty eating and self-criticismmay finally be on the way.（分数：71.00）(1).The re

48、search findings on the lab mice suggest that some people, if not all, have trouble controlling weight because of defects in the ob gene.（分数：7.10）填空项 1:_(2).The discovery of a magical cure called leptin, as reported in Science met with unusual excitement in the United States.（分数：7.10）填空项 1:_(3).As a weight-loss means; Leptin does not have the side effect of drastic reduction i