大学四级-145及答案解析.doc

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1、大学四级-145 及答案解析(总分：693.00，做题时间：90 分钟)一、BPart Writing(总题数：1，分数：106.00)1.B Building a Good Teacher-Student Relationship/B 1. 良好的师生关系是教学成功的根本保障。 2. 以个人经历举例说明良好的师生关系是双方共同努力的结果。 3. 如何对待师生可能存在的误解。（分数：106.00）_二、BPart Reading (总题数：1，分数：70.00)B Weight-Loss Nirvana?A Substance That Makes Fat Mice Thin Just Mig

2、ht Work for Humans Too/BIn the US, where one in three adults is seriously overweight, the news carried by the journal Science last week - that Friedman and his colleagues at the Howard Hughes Medical Institute and New York Citys Rockefeller University had discovered a magical dose that melts fat in

3、a matter of weeks - resonated 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 California that holds the license on the underlying technology. It is too early to predict, however, wheth

4、er 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 goes well, it could be five to ten years before leptin is approved in the US for human use. Researchers must f

5、irst demonstrate that leptin benefits people as well as animals and that it causes no serious side effects.The search for leptin began in the 1960s, when Douglas Coleman, a researcher at the Jackson Laboratory in Bar Harbor, Maine, began studying a strain of fat laboratory mice. In a series of creat

6、ive 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 astonishing: the fat animal immediately began to lose weight. This suggested that the blood of non-obese mice carr

7、ied 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 that no one was able to isolate it.Friedman picked up the challenge, applying new tools developed by the field of

8、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 enough, late last year, after eight years of effort, Friedman and his colleagues pinpointed the ob gene in both avera

9、ge-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.By injecting leptin into obese mice, three separate teams of researchers, including Friedmans, have confirmed that this protein is i

10、ndeed 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 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

11、 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, body temperature drops, and metabolism slows; when leptin is high, everything reverses. In such fashion, the br

12、ain strives to keep body weight stable and fluctuations small.Because leptin is produced in fat tissue (组织), the fatter an animal is, the more leptin its cells should make. Normal mice then respond to weight gain by turning out more leptin. As a result, their appetites slow down and their energy con

13、sumption 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, and then when we give them the protein, they get thin because they think theyre fat!“What, if anything, does th

14、is 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 off kilos because of mutation (突变) in this gene. Most experts, however, agree that defects in the ob gene are not

15、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 example, a team of researchers from the pharmaceutical company Hoffmann-LaRoche described how they fattened lean mi

16、ce 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 may have value in reversing more typical cases of weight gain.What about side effects? Injections of leptin do not, a

17、s 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 mice likewise reach an ideal leanness, and then stop losing weight. The pattern of weight loss is also encouraging.

18、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 Rockefeller University $ 20 million for patent rights to make products based on the ob gene) has announced that it hopes to be

19、gin making human trials as early as next year. Many experts find these plans too optimistic. Just because researchers have not noted worrisome side effects yet, critics say, does not mean that none will emerge. Leptin, they point out, is a serious drug, not the easy-to-swallow “thin pill“ dieters ha

20、ve 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 week, the obese mice started regaining weight as soon as the injections stopped. Even with a boost from something like l

21、eptin, 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 the hard way,“ he predicts. “Itll be like diabetes: you still have to exercise and watch your food intake.“Regardless

22、 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 understood metabolic pathway, one that probably consists of many other equally powerful compounds, each of which could lead to n

23、ew drugs. To the millions of seriously overweight Americans, help with a frustrating condition - years of guilty eating and self-recrimination - may finally be on the way.（分数：70.00）(1).Leptin is effective in reducing weight but its many years away before humans can use it.（分数：7.00）填空项 1:_(2).Leptin,

24、 after being approved by health authorities, will be available to people in need through doctors prescriptions.（分数：7.00）填空项 1:_(3).Both obese mice and normal mice have the ob gene.（分数：7.00）填空项 1:_(4).Both obese mice and normal mice can produce leptin in their bodies.（分数：7.00）填空项 1:_(5).Dr. Friedman

25、never found the gene that was believed to control weight. Instead, he found leptin.（分数：7.00）填空项 1:_(6).If excess leptin is present, the brain signals the body to increase food intake and to become more active.（分数：7.00）填空项 1:_(7).The ob gene causes the fat cells to produce the hormone leptin. The fat

26、ter, the more hormones are produced.（分数：7.00）填空项 1:_(8).Leptin plays an important role in adjusting _ and metabolism.（分数：7.00）填空项 1:_(9).After being _ leptin, the obese mice start consuming less food and burning more fat, which is confirmed by Friedman together with three separate teams of researche

27、rs.（分数：7.00）填空项 1:_(10).In response to _, normal mice will turn out more leptin that will speed up their energy consumption.（分数：7.00）填空项 1:_三、BPart Listenin(总题数：3，分数：105.00)Questions 11 to 18 are based on the conversation you have just heard.（分数：56.00）A.The man asks Carol to attend Mr. Whites class

28、with him.B.The man asks Carol to lend him the notes from the history class.C.If Mr. White had a history class last Monday.D.The man asks Carol for the notes from the science class.A.The man thinks his rent is very cheap.B.The man thinks his rent is very expensive.C.The man thinks he lives in a good

29、area.D.The man thinks his rent is reasonable.A.The man wants to see a thrilling movie.B.The man really loves watching romance movies.C.The man doesnt want to see a movie.D.The man wants to see an action movie.A.He knows her from their elementary school science class.B.She knows him from computer sci

30、ence class.C.They went to the same high school.D.She is his sister.A.The man is thinking of going around the world for a third time.B.The woman wants to go on vacation.C.James wants to go on vacation.D.The man hasnt decided where to go on vacation.A.The woman is thinking about applying for a job.B.T

31、hey are discussing a movie.C.They are planning a surprise party for a friend.D.The man is applying for university.A.Kim is addicted to cleaning.B.Kim is usually reliable.C.They all enjoy cleaning.D.They wish that Kim would be more focused on the housework.A.Doctor and patient.B.Student and teacher.C

32、.Sales assistant and customer.D.Manager and office clerk.Questions 19 to 22 are based on the conversation you have just heard.（分数：28.00）A.A house.B.A car.C.A hotel.D.An art gallery.A.He has many pets.B.He has three children.C.He doesnt need a larger house.D.His wife is pregnant.A.House sales company

33、.B.Motor sales company.C.Food sales company.D.Travel agency.A.She is a travel agent.B.She is a (real) estate agent.C.She sells cars.D.She sells hotels.Questions 23 to 25 are based on the conversation you have just heard.（分数：21.00）A.A project about an actress.B.A project about a movie director.C.A pr

34、oject about a movie.D.A project about Europe.A.Going to the cinema.B.Buying some DVDs.C.Doing an internet search.D.Reading a magazine.A.Her mother.B.An actress.C.Her roommate.D.Her classmate.四、BSection B/B(总题数：3，分数：70.00)BPassage OneQuestions 26 to 28 are based on the passage you have just heard./B（

35、分数：21.00）A.31st December.B.25th December.C.1st January.D.25th November.A.Flowers.B.Fruit and nuts.C.Christmas trees.D.Rainbows and sunshine.A.Jesus Christ.B.Santa Claus.C.Father Christmas.D.Mary.BPassage TwoQuestions 29 to 31 are based on the passage you have just heard./B（分数：21.00）A.History teacher

36、.B.College professor.C.History writer.D.Campaign manager.A.Somewhere over the Atlantic.B.Somewhere over the Pacific.C.Somewhere over New York.D.Somewhere over London.A.National Geographic Channel.B.HBO.C.BBC.D.History Channel.BPassage ThreeQuestions 32 to 35 are based on the passage you have just he

37、ard./B（分数：28.00）A.Tiny.B.Ankle biter.C.Elf.D.Gnome.A.Kirk.B.John.C.Jack.D.Tom.A.Reaching things on shelves.B.Seeing over the hood of his car.C.Carrying his luggage.D.Riding his bicycle.A.Because he enjoys the music.B.In order to see the concert.C.To lose weight.D.For exercise.五、BSection C/B(总题数：1，分数

38、：77.00)The home secretary, Charles Clarke, will today guarantee that the personal details contained on the national identity card will not go beyond those currently on passports. He will write theU (36) /U into the legislation which passes through its finalU (37) /Uin the Commons today.The billU (38

39、) /Uthat only name, date and place of birth, gender, address, nationality and immigrationU (39) /Ucan be recorded on the ID database. The home secretary has promised fresh legislation will have to be introduced if extra personal details such as health records,U (40) /U records or other background in

40、formation were added.Mr. Clarke will also promise that everyone will be able to access their entry on the national ID card database and see which organizations had been U(41) /U their identity. At the same time ministers will table new government amendments to ensure those who U(42) /U the national

41、ID cards register will not be able to tell who has a criminal record on the policeU (43) /Ucomputer.U (44) /U. The Home Office has opened talks with departments likely to benefit from the introduction of the scheme to see if they can recoup some of the overall costs.U (45) /U.The Home Office ministe

42、r, Andy Burnham, said scanners and readers needed for the national identity card scheme would have to be introduced anyway to upgrade to the next generation of “biometric“ passports. He said other departments which would make savings as a result of the introduction of ID cards would make a contribut

43、ion.U (46) /U（分数：77.00）(1).（分数：7.00）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:_填空项 1:_六、BPart Reading (总题数：1，分数：90.00)This book is about the future of technology. In it we will examine some of the many recent developments in a few key fields and try, in a U(47) /U way, to

44、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 U(48) /U force of our time and probably of all time to come. It appears in more U(49) /U than we can count. It changes so rapidly that no scientist or engineer can keep up wi

45、th his own field, much less with technology in general. It has U(50) /U 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 U(51) /U the details of its future changes.Yet the task is well worth undertaking. Whatever hints we c

46、an gather about the future will help us prepare for the changes to come. And though technology has made the present much less U(52) /U than the past, and surely will make the future more disturbed, still, there is good reason to hope that our lives, in sum and on average, will be better as a result.

47、 In an age of uncomfortable U(53) /U , this is reassurance we all can use.For an idea of what is to come - in magnitude if not in specifics - look to the past. In the last ninety years, the world has shrunk, while human experience has U(54) /U almost beyond the recognition of those who grew up in our grandparents generation.A century after Americas founders U(55) /U their agrarian (耕地的) democracy, nearly all their descendents still lived on farming. Since World War I, te