1、大学英语六级模拟试卷 168及答案与解析 一、 Part I Writing (30 minutes) 1 Directions: For this part, you are allowed thirty minutes to write a composition on the topic:“ What Do You Think of Challenge?“. You should write at least 150 words and you should base your composition on the outline ( given in Chinese) below: 1
2、. 挑战的意义； 2.如何迎接挑战； 3.我的看法 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attached to the passage. For questions 1-4, mark： Y (for YES) if the statement agrees with the in
3、formation given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 1 Part Reading Comprehension (Skimming and Scanning) Directions: In this part, you will have 15 minutes to go over the pass
4、age quickly and answer the questions on Answer Sheet 1. For questions 1-4, mark Y (for YES) if the statement agrees with the information given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVRN) if the information is not given in the passa
5、ge. For questions 5-10, complete the sentences with the information given in the passage. Unity and Diversity Many physicists are engaged in the search for a “theory of everything“. Biologists, smugly, think they have found one already. Organisms that survive long enough to reproduce and are attract
6、ive enough to find a mate pass their genes on to the next generation. Those that do not are evolutionary cul-de-sacs. But the details how you go on from the basic principles of evolution to explain large-scale patterns in biology are more divisive. Scientific camps form. Their leaders step onto soap
7、 boxes. And only rarely do people concede that their own theories and those of their opponents are not always mutually exclusive. Since the early 1970s, the two grandest patterns of life how species are arranged in space and how they are arranged in time have divided their opposing camps quite neatl
8、y. Those who squabble over space disagree about why there are more species in the tropics than anywhere else. To them, the tropics are either where species are more often born (cradles of diversity) or where they tend not to die (museums of diversity). By contrast, biologists concerned with patterns
9、 in time tenaciously debate whether new species come into being in a smooth and gradual manner, or whether the history of life is actually a series of bursts of change that are interspersed with periods when nothing much happens. Two papers just published in Science have cast light on these question
10、s, and their findings, if not necessarily resulting in compromise, do show the value of taking leaves out of other peoples books. The “space biologists“ have looked into time, namely the fossil record over the past 11m years. Meanwhile the “time biologists“ have looked at the here and now and found
11、evidence in living species for periods of rapid evolution in their genes. Biological Spacetime The space biologists have the advantage that they agree about the pattern they are trying to explain. Almost all groups of life that have been studied be they fungi, plants, vertebrates or invertebrates, a
12、nd no matter whether they occur in forests, streams or seas seem to have more species the closer they are to the equator. To decide whether the tropics are a cradle or a museum, though, involves picking this pattern apart with statistics. And statistics work best when you have more than one sample.
13、That is the reason for reaching into the past. David Jablonski, of the University of Chicago, and his colleagues created their samples by dividing the past 11m years into three periods. For simplicitys sake, they also chopped the Earths surface into two: tropical regions and everywhere else, which t
14、hey called the “extratropics“. To avoid sampling bias, they restricted their analysis to one group of animals the bivalve molluscs that fossilise well. This allowed them to follow 431 “lineages“ of marine bivalve through the course of geological time. The vast majority of these lineages appear in th
15、e tropics and then spread into the extratropics, in other words, the tropics do, indeed, act as cradles of biodiversity. In fact, the pattern Dr Jablonski reports is probably more marked than his data suggest. That is because palaeontologists themselves are generally a temperate species and are most
16、 commonly found in the northern hemisphere. That means rocks in this region have been oversampled compared with those in the tropics. Also, tropical rocks tend to experience deep weathering, rarely poking above the ground as outcrops. That makes sampling them harder, even if you bother to look in th
17、e first place. The tropics do, indeed, act as cradles of biodiversity. Both of these facts mean it is likely that some lineages which seem to make their first appearance in the extratropical fossil record actually started out near the equator. The cradle hypothesis, then, looks strong. But that does
18、 not necessarily mean the museum hypothesis is wrong for, at the same time as the tropics were generating diversity they seem to have been preserving it as well. Although the bivalve lineages Dr Jablonski studied spread out from the equator in waves, they did not become extinct in the wake of these
19、waves. Instead of being forced out of tropical regions as they travelled poleward, they accumulated there. Common ground appears to be forming in time biology as well. The dispute is between the gradualists and those who think that the sudden shifts in fossil types seen in the geological record are
20、real, rather than a consequence of the irregular way that rocks are laid down. It got rather personal a few years ago, with references to evolution by creeps and evolution by jerks. But, in a similar way to Dr Jablonskis study, which suggests that models of cradles and museums present a false dichot
21、omy, a paper from a member of the gradualist camp of time biology endorses some features of jerky evolution. Some Jerks, Some Creeps Mark Pagel and his colleagues at the University of Reading, in England, reasoned that the theory of punctuated equilibria (the formal name given to evolution in bursts
22、) predicts a relation between the rate at which new species are formed and the rate of genetic change in an organisms recent past. A lineage that has spun off a lot of species will show more genetic change than one that has not. The alternative view, that evolutionary changes tick along gradually, s
23、uggests mutations would accumulate incrementally as time goes by, independently of how many new species a lineage spins off. Dr Pagel studied 122 family trees this way. He found that in about a third of them, there was more change in the DNA in those trees where more species had been generated. He a
24、lso found that punctuated evolution explained about 22% of such genetic changes, with the remainder unfolding smoothly through time. This means, among other things, that when biologists have calculated how long ago two lineages diverged by assuming change is regular, they may have their dates wrong.
25、 Both Dr Jablonski and Dr Pagel, then, have found a degree of resolution between opposing ideas by persistently hacking away at the data. Both have also posed more questions to their respective fields. Why does punctuation contribute more to some lineages than to others? (Plants and fungi are more a
26、ffected than animals.) How do lineages spread into the colder climates of higher latitudes? Some of the old questions, though, are still rattling around like skeletons in a cupboard. Dr Jablonskis study does not, for instance, help to answer whether the tropics are a wellspring of species because a
27、hotter climate brings a higher mutation rate, or because more intense interactions between species select for more rapid evolutionary change. In the spirit of compromise, there seems no reason why it could not be a bit of both. 2 New insights into the origin of species suggest that biologists disagr
28、ee less than they thought they did. （ A） Y （ B） N （ C） NG 3 The closer to the extratropics, the more species there are. （ A） Y （ B） N （ C） NG 4 The bivalve lineages were forced out of tropical regions. （ A） Y （ B） N （ C） NG 5 Dr Pagel studied 122 family trees in that there were more genetic changes
29、in them. （ A） Y （ B） N （ C） NG 6 To space biologists, the tropics are either cradles of diversity or _. 7 David Jablonski and his colleagues divided the Earths surface into two: _ and the “extratropics“. 8 Rocks in _ have been oversampled compared with those in the tropics. 9 Among the time biologis
30、ts, the gradualists believe in evolution by _. 10 The term punctuated equilibria refers to _. 11 Both Dr Jablonski and Dr Pagel have found _ between opposing ideas. Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, o
31、ne or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer. （ A） Anna, the cook. （ B） A
32、nna and Linda. （ C） Anna, Linda and the cook. （ D） Anna, Linda and the visitor. （ A） The man. （ B） The woman. （ C） Both the man and the woman. （ D） The woman did while the man didnt. （ A） On the 6th of December. （ B） On the 7th of December. （ C） On the 26th of December. （ D） On the 27th of December.
33、 （ A） The man thinks tile woman is wasting her time. （ B） The man thinks the woman should make full use of her time. （ C） The man is eager to know the womans answer. （ D） The man can wait and there is no need for her to hurry. （ A） Language courses. （ B） Universities. （ C） British and American Engli
34、sh. （ D） Literature courses. （ A） A professor and a student. （ B） A hotel manager and a tourist. （ C） A salesman and a customer. （ D） A store owner and his manager. （ A） Only Mr. Woods wallet was lost. （ B） Hell pick up his wallet and identity card at the bank. （ C） Hell not go to the bank and the p
35、ost office. （ D） Hell pick up his wallet and identity card. （ A） He wanted to ask the doctor some questions. （ B） He wanted to see the doctor. （ C） He wanted to pay the doctor. （ D） He wanted to see the nurse. （ A） At a fair. （ B） At a cafeteria. （ C） In a computer lab. （ D） In a shopping mall. （ A）
36、 The latest computer technology. （ B） The organizing of an exhibition. （ C） The purchasing of some equipment. （ D） The dramatic changes in the job market. （ A） Data collection. （ B） Training consultancy. （ C） Corporate management. （ D） Information processing. （ A） The apartment is too far from the c
37、ampus. （ B） The dishwasher broke down. （ C） Shes having trouble with the owner of the apartment. （ D） Her roommate wont share expenses. （ A） Mary didnt pay the rent on time. （ B） She couldnt find anyone to repair the dishwasher. （ C） She had to buy a new dishwasher. （ D） Mary had the dishwasher repa
38、ired without her permission. （ A） She has decided to bear the cost herself. （ B） She has sent the bill to Ms. Black. （ C） She has deducted the cost from the rent check. （ D） She has asked her roommate, Susan, to share it. （ A） To find another apartment. （ B） To talk to Ms. Black. （ C） To ask Tom to
39、repair the dishwasher. （ D） To buy Tom a new dishwasher for the owner. Section B Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must cho
40、ose the best answer from the four choices marked A, B, C and D. （ A） It learns to say by imitating what people say. （ B） It learns to say by imitating what people hear. （ C） It learns to say by thinking. （ D） It learns to say by seeing. （ A） To imitate it. （ B） To use it from time to time. （ C） To a
41、sk for it. （ D） To hear it. （ A） We should read first. （ B） We should spell first. （ C） We should listen first. （ D） We should write first. （ A） They have nothing to do with each other. （ B） They have something to do with each other. （ C） They help each other in a way. （ D） They depend on each other
42、. （ A） Other living things change their environment while man doesnt. （ B） Man alters his environment while he is adapted to it, but other living things do not. （ C） Other living things is not only adapted to their environment but also alters it. （ D） Man is only adapted to the environment but he do
43、esnt alter it. （ A） The relationship between man and his environment. （ B） The relationship between living things and their environment. （ C） The relationship between man and living things. （ D） The relationship between mans brain and other living things. （ A） To study how students remember English
44、vocabulary by short-term memory. （ B） To study how students learn English vocabulary. （ C） To study how to develop students ability in English. （ D） To study how long information in short-term memory is kept. （ A） Information in short-term memory is different from that in long-term memory only in co
45、ntent. （ B） Long-term memory can be achieved only by training. （ C） It is easier to test short-term memory than long-term memory. （ D） Henning gave a test on vocabulary to his subjects. （ A） Beginners have difficulty distinguishing the pronunciation of words. （ B） Advanced students remember words by
46、 their meaning. （ C） It is difficult to remember words that have the same meaning. （ D） It is difficult to remember words that sound alike. （ A） Memory. （ B） Two kinds of memory. （ C） Short-term memory. （ D） An experiment on students. Section C Directions: In this section, you will hear a passage th
47、ree times. When the passage is read for the first time, you should listen carefully for its general idea. When the passage is read for the second time, you are required to fill in the blanks numbered from 36 to 43 with the exact words you have just heard. For blanks numbered from 44 to 46 you are re
48、quired to fill in the missing information. For these blanks, you can either use the exact words you have just heard or write down the 36 Advertisers can use 【 B1】 _ media, or means, to deliver their sales messages. The 【 B2】 _ media are newspapers, magazines, television, radio, direct mail, outdoor
49、【 B3】 _ , and point-of-sale or point-of-purchase advertising. Which single medium or 【 B4】 _ of media is used depends on the product, the market area in which the company 【 B5】 _ , the income group to which the product appeals, and other 【 B6】 _ . Newspapers are the oldest 【 B7】 _ medium in the United States. The newspaper, with its fresh stream of news and features, 【 B8】 _ a high degree of reader interest every day.【 B9】 _
