[外语类试卷]大学英语六级模拟试卷76及答案与解析.doc

1、大学英语六级模拟试卷 76及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a composition on the topic Test for National Civil Servants. You should write at least 150 words according to the suggestions given below in Chinese: 1近几年兴起了一股国家公务员考试 (Test for National Civil Serv

2、ants)热 2产生这种现象的原因 3我的看法 Test for National Civil Servants 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 t

3、he 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 GIVEN) if the information is not given in the passage. 2 Why leaves change colors If you are lucky, you live in one of those parts of the world whe

4、re Nature has one last fun before settling down into winters sleep. In those lucky places, as days shorten and temperatures become crisp, the quiet green palette(调色板 ) of summer leaves is transformed into the vivid autumn palette of reds, oranges, golds, and browns before the leaves fall off the tre

5、es. On special years, the colors are truly breathtaking, How does autumn color happen? For years, scientists have worked to understand the changes that happen to trees and shrubs in the autumn. Although we dont know all the details, we do know enough to explain the basics and help you to enjoy more

6、fully Natures multicolored autumn farewell. Three factors influence autumn leaf color-leaf pigments(色素 ), length of night, and weather, but not quite in the way we think. The timing of color change and leaf fall is primarily regulated by the calendar. That is, the increasing length of night. None of

7、 the other environmental in flounces -temperature, rainfall, food supply, and so on are as unvarying as the steadily increasing length of night during autumn. As days grow shorter, and nights grow longer and cooler, biochemical processes in the leaf begin to paint the landscape with Natures autumn p

8、alette. Where do autumn colors come from? -A color palette needs pigments, and there are three types that are involved in autumn color. Chlorophyll(叶绿素 ),which gives leaves their basic green color. It is necessary for photosynthesis(光合作用 ), the chemical reaction that enables plants to use sunlight t

9、o manufacture sugars for their food. -Carotenoids(类胡萝卜素 ), which produce yellow, orange, and brown colors in such things as corn, carrots, and daffodils. -Anthocyanins(花青素 ), which give color to such familiar things as red apples, grapes, blue berries, cherries, strawberries, and plums. They are wat

10、er soluble and appear in the watery liquid of leaf cells. Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells. During the grow

11、ing season, chlorophyll is continually being produced and broken down and leaves appear green. As night length increases in the autunm, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids and anthocyanins that are present in the leaf are

12、then unmasked and show their colors. Certain colors are characteristic of particular species. Oaks turn red, brown, or russet; hickories, golden bronze; aspen and yellow-poplar, golden yellow; dogwood, purplish red. Maples differ species by species: red maple turns brilliant scarlet; sugar maple, or

13、ange-red; and black maple, glowing yellow. Leaves of some species such as the elms simply shrink and fall, exhibiting little color. The timing of the color change also varies by species. Sourwood in southern forests can become vividly colorful in late summer while all other species are still vigorou

14、sly green. Oaks put on their colors long after other species have already shed their leaves. These differences in timing among species seem to be genetically inherited, for a particular species at the same latitude will show the same coloration in the cool temperatures of high mountains at about the

15、 same time as it does in warmer lowlands. How does weather affect autumn color? The amount and brilliance of the colors that develop in any particular autumn season are related to weather conditions that occur before and during the time the chlorophyll in the leaves is decreasing. Temperature and mo

16、isture are the main influences. A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf preve

17、nt these sugars from moving out. These conditlons lots of sugar and lots of light spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimsoil. Because carotenoids are always present in leaves, the yellow and gold color remain fairly constant from year to year. The a

18、mount of moisture in the soil also affects autumn colors. Like the weather, soil moisture varies greatly from year to year. The countless combinations of these two highly variable factors assure that no two autumns can be exactly alike. A late spring, or a severe summer drought, can delay the onset

19、of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most brilliant autumn colors. What triggers leaf fall? In early autumn, in response to the

20、 shortening days and declining intensity of sunlight, leaves begin the processes leading up to their fall. The veins that carry fluids into and out of the leaf gradually close off as a layer of cells forms at the base of each leaf. These clogged veins trap sugars in the leaf and promote production o

21、f anthocyanins. Once this separation layer is complete and the connecting tissues are sealed off, the leaf is ready to fall. What does all this do for the tree? Winter is a certainty that all vegetation in the temperate zones must face each year. Evergreen plants, including trees, must have some sor

22、t of protection to survive freezing temperatures and other harsh wintertime influences. Stems, twigs, and buds are equipped to survive extreme cold so that they can reawaken when spring informs the start of another growing season. Tender leaf tissues, however, would freeze in winter, so plants must

23、either toughen up and protect their leaves or dispose of them. The evergreens pines, spruces, cedars, firs, and so on are able to survive winter because they have toughened up. Their needle-like or scale like leaf is covered with a heavy wax coating and the fluid inside their cells contains substanc

24、es that resist freezing. Thus the leave of evergreens can safely withstand all but the severest winter conditions, such as those in the Arctic. Evergreen need les survive for some years but eventually fall because of old age. The leaves of broad leaved plants, on the other hand, are tender and vulne

25、rable to damage. These leaves are typically broad and thin and are not protected by any thick coverings. The fluid in ceils of these leaves is usually a thin, watery sap, that freezes readily. This means that be cells could not survive winter where temperatures fall below freezing. Tissues unable to

26、 endure winter must be sealed off and shed to ensure the plants continued survival. Thus leaf fall precedes each winter in the temperate zones. When is the best time to see autumn color? Unfortunately, autumn color is not very predictable. But it generally starts in late September in New England and

27、 moves southward, reaching the Smoky Mountains by early November. It also appears about this time in the high mountains of the West. Remember that cooler high. positions will color up before the valleys, The Forest Services Fall Color Hotline (1-800-354-4595) can provide you with details as the autu

28、mn color display progresses. 2 In some places leaves will fall off the trees before they change colors in the autumn. （ A） Y （ B） N （ C） NG 3 Up until now, scientists still could not explain how leaves will change colors during the fall. （ A） Y （ B） N （ C） NG 4 The increasing length of night is the

29、most stable factor among all the environmental influences on leaves change. （ A） Y （ B） N （ C） NG 5 The precondition of the appearance of anthocyanins is there is sugar in the leaf cells. （ A） Y （ B） N （ C） NG 6 Leaves show different colors other than green in the fall because the carotenoids and an

30、thocyanins are then_. 7 The example that Sourwood changes colors before other species do illustrate that the timing of color change_. 8 When the chlorophyll is decreasing, _are the most important weather conditions affect the color displays of leaves. 9 The process that the veins gradually close off

31、 and trap sugars in the leaves will cause leaves_. 10 The leaves of evergreens can survive the winter because they are _and fluid inside their cells contains cold-resisting substances. 11 Broadleaved plants in the temperate zones begin to shed their leaves before winter because they cannot_. Section

32、 A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one 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

33、the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer. （ A） Nick cant go on studying because he has to work in a steel plant. （ B） Nick has earned enough money for his senior year. （ C） Nick prefers working in a steel plant to going to college. （ D） Nick

34、 doesnt have enough money so hell work during his senior year. （ A） The woman has talked with Manager Li once about the proposal. （ B） The woman called Manager Li at 1:30 to talk about the proposal. （ C） The woman will not know Manager Lis decision until 1:30. （ D） The woman didnt get through Manage

35、r Lis secretary at lunch time. （ A） Save time by using a computer. （ B） Buy her own computer. （ C） Borrow Marys computer. （ D） Stay home and complete her paper. （ A） He didnt get the book he needed. （ B） He had no idea where the book was. （ C） The library is closed on weekend. （ D） He was not allowe

36、d to check out the book. （ A） She offered to drive the man to Paris. （ B） She offered to serve as a tour guide to the man. （ C） She offered to teach the man French in case of trouble. （ D） She offered to accompany the man to go to Paris. （ A） The man is thinking about taking a new job. （ B） The man

37、likes the job that enables him traveling. （ C） The man is sure that he can gain more by taking the job. （ D） The man doesnt want to stay home and take care of his child. （ A） Shes learned a lot from the literature class. （ B） Shes writing some books about world classics. （ C） Shes met some of the wo

38、rlds best writing. （ D） Shes just back from a trip around the world. （ A） Move out of the South Dorm. （ B） Find a bigger room. （ C） Look for a room in the South Dorm. （ D） Stay where she lives now. （ A） To get materials for a class she missed. （ B） To discuss an assignment she is working on. （ C） To

39、 ask a question about a video her class recently watched. （ D） To inform the professor of changes in her schedule. （ A） He remembers that he does not have the video in his office. （ B） He realizes that the woman does not have a VCR. （ C） He is worried that he will not have the video back in time for

40、 his class. （ D） He realizes that he will not need the video from Friday to next week. （ A） To return the video to the professor. （ B） To get the video from the professor. （ C） To hand in an assignment to the professor. （ D） To discuss handouts with the professor. （ A） Protecting buyers of paintings

41、. （ B） Why copies of famous paintings are made. （ C） How paintings are sold in the United States. （ D） Protecting artists from illegal use of their work. （ A） The United States Copyright Office created it. （ B） It does not protect artists techniques and procedures. （ C） It has not been changed since

42、 its creation. （ D） It is applied only to copies of the original work. （ A） After the artwork is reviewed by lawyers. （ B） After all documents are filed. （ C） When the artist first gets an idea. （ D） The moment the work of art is finished. （ A） The buyer has the right to reprint it. （ B） The buyer i

43、s allowed to change it. （ C） The artist continues to hold the copyright for it. （ D） The artist must report the sale to the authority. 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 w

44、ill be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D. （ A） It is sure that the use illegal drugs call cause life-long dependency. （ B） The children who smoke will have their life shorten. （ C） Columbia University on Drugs has

45、studied the problems of smoking. （ D） Most eighth graders use illegal drugs. （ A） Educating students. （ B） Changing the dangerous trends. （ C） Arresting those criminals. （ D） Punishing those drug users. （ A） Robbery. （ B） Delinquency. （ C） Stealing. （ D） Premature sexual activity. （ A） Your accompli

46、shments. （ B） Your hobbies. （ C） Your family members. （ D） Your appearance. （ A） In some large community. （ B） In most colleges or high schools. （ C） In the companies that offer jobs. （ D） In school libraries. （ A） It may have a lot of fun. （ B） Its a good opportunity for people to know the society.

47、 （ C） Its one of the most difficult jobs. （ D） Its a challenge for peoples ability. （ A） It was born in New York. （ B） It is a kind of music as a style of playing. （ C） Hearing jazz, people want to dance to the music. （ D） It is played with strong beat. （ A） Streets in the French Quarter. （ B） Prese

48、rvation Hall. （ C） Parks in New Orleans. （ D） Theatres in France. （ A） Because the salaries of players are low. （ B） Because the players are getting old. （ C） Because no one wants to hear it again. （ D） Because Preservation Hall is closed. （ A） A music critic. （ B） A famous player. （ C） A music hist

49、orian. （ D） A composer. Section C Directions: In this section, you will hear a passage three 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 required to fill in the missing information. For these blanks, you can either use the exact words you have j