大学六级-874及答案解析.doc

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1、大学六级-874 及答案解析(总分：712.00，做题时间：90 分钟)一、Part Writing(总题数：1，分数：106.00)1.简述在大学里学生会和各种社团的现状2参加学生会和各种社团对个人的有利之处3你对参加学生会和社团活动的态度（分数：106.00）_二、Part Reading Compr(总题数：1，分数：70.00)RiversBy original usage, a river is flowing water in a channel with defined banks. Modern usage includes rivers that are multichann

2、eled, intermittent, or transient in flow and channels that are practically bankless. The concept of channeled surface flow, however, remains central to the definition.Rivers are nourished by precipitation, by direct overland runoff, through springs and seepages (渗流), or from meltwater at the edges o

3、f snowfields and glaciers. The contribution of direct precipitation on the water surface is usually minute, except where much of a catchment area is occupied by lakes. River water losses result from seepage into shallow or deep aquifers (沙石含水层) and particularly from evaporation. The difference betwe

4、en the water input and loss sustains surface discharge or streamflow. The amount of water in river system at any time is but a tiny fraction of the Earths total water; 97 percent of all water is contained in the oceans and about three-quarters of fresh water is stored as land ice; nearly all the rem

5、ainder occurs as groundwater. Lakes hold less than 0.5 percent Of all fresh water, soil moisture accounts for about 0.05 percent, and water in river channels for roughly half as much, 0.025 percent, which represents only about one four-thousandth of the Earths total fresh water.Water is constantly c

6、ycled through the systems of land ice, soil, lakes, groundwater, and river channels, however. The discharge of rivers to the oceans delivers to these systems the equivalent of the water vapor that is blown overland and then consequently precipitated as rain or snow i.e., some 7 percent of mean annua

7、l precipitation on the globe and 30 percent of precipitation on land areas.The historical record includes marked shifts in the appreciation of rivers, numerous conflicts in use demand, and an intensification of use that has rapidly accelerated during the 20th century. External freight trade became c

8、oncentrated in estuarine ports rather than in inland ports when oceangoing vessels increased in size.Demand on open-channel water increases as population and per capita water use increase and as underground water supplies fall short. Irrigation use constitutes a comparatively large percentage of the

9、 total supply.Present-day demands on rivers as power sources range from the floating of timber, through the use of water for cooling, to hydroelectric generation. Logging in forests relies primarily on notation during the season of melt-water high flow. Large power plants other industrial facilities

10、 are often located along .rivers, which supply the enormous quantities of water needed for cooling purposes. Manufacturers of petrochemicals, steel, and woolen cloth also make large demands. Hydroelectric power generation was introduced more than 100 years ago, but the majority of the existing insta

11、llations have been built since 1950.The ever-increasing exploitation of rivers has given rise to a variety of problems. Extensive commercial navigation of rivers has resulted in much artificial improvement of natural channels, including increasing the depth of the channels to permit passage of large

12、r vessels. In some cases, this lowering of the fiver bottom has caused the water table of the surrounding area to drop, which has adversely affected agriculture. Also, canalization, with its extensive system of locks and navigation dams, often seriously disrupts river in ecosystems.An even more far-

13、reaching problem is that of water pollution. Pesticides and herbicides are now employed in large quantities throughout much of the word. The widespread use of such biocides and the universal nature of water make it inevitable that the toxic chemicals would appear as stream pollutants. Biocides can c

14、ontaminate water, especially of slow-flowing rivers, and are responsible for a number of fish kills each year.In agricultural areas the extensive use of phosphates (磷酸盐) and nitrates (硝酸盐) as fertilizers may resulting other problems. Entering rivers via rainwater runoff and groundwater seepage, thes

15、e chemicals can cause eutrophication (超营养作用). This process involves a sharp increase in the concentration of phosphorus, nitrogen, and other plant nutrients that promotes the rapid growth of algae in sluggish rivers and a consequent depletion of oxygen in the water. Under normal conditions, algae co

16、ntribute to the oxygen balance in rivers and also serve as food for fish, but in excessive amounts they crowd out populations of other organisms, overgrow and finally die due to the exhaustion of available nutrients and autointoxication. Various species of bacteria then begin to decay and putrefy th

17、e dead algal bodies, the oxidation of which sharply reduces the amount of oxygen in the river water. The water may develop a bad taste and is unfit for human consumption unless filtered and specially treated.Urban centers located along rivers contribute significantly to the pollution problem as well

18、. In spite of the availability of advanced waste-purification technology, a surprisingly large percentage of the sewage from cities and towns is released into waterways untreated. In effect, rivers are used as open sewers for municipal wastes, which results not only in the direct degradation of wate

19、r quality but also in eutrophication.Still another major source of pollutants is industry. Untreated industrial chemical wastes can alter the normal biological activity of rivers, and many of the chemicals react with water to raise the acidity of rivers to a point where the water becomes corrosive e

20、nough to destroy living organisms. An example of this is the formation of sulfuric acid from the sulfur laden residue of coalmining operations. Although upper limits for concentrations of unquestionably toxic chemicals have been established for drinking water, no general rules exist for the treatmen

21、t of industrial wastes because of the wide variety of organic and inorganic compounds involved. Moreover, even in cases where a government-imposed ban checks the further discharge of certain dangerous substances into waterways, the chemicals may persist in the environment for years. Such is the case

22、 with PCBs (多氯化联苯). Since PCBs cannot be broken down by conventional waste treatment methods and are degraded by natural processes very slowly, scientists fear that these compounds will continue to pose a serious hazard for decades to come. PCBs have been found in high concentrations in the fatty ti

23、ssues of fish, which can be passed up the food chain to humans. An accumulation of PCBs in the human body is known to induce cancer and other severe disorders.As noted above, many industrial facilities, including nuclear power plants, steel mills, chemical-processing facilities, and oil refineries,

24、use large quantities of water for cooling and return it at elevated temperatures. Such heated water can alter the existing ecology, sometimes sufficiently to drive out or kill desirable species of fish. It also may cause rapid depletion of the oxygen supply by promoting algal blooms.（分数：70.00）(1).Or

25、iginal usage refers to rivers that _ .（分数：7.00）A.are multichanneled in flowB.have clear banksC.include bankless channelsD.exist for only a short time in flow(2).The fiver water makes up _ of the Earths total fresh water.（分数：7.00）A.less than 0.5 percentB.nearly 0.05 percentC.about three-quartersD.abo

26、ut one four-thousandth(3).The ever-increasing exploitation of rivers has resulted in various problems except _ .（分数：7.00）A.decrease of the depth of the channelsB.fall of the water table of the surrounding areaC.destruction of the rivers in ecosystemsD.water pollution(4).Algae under normal conditions

27、 in rivers _ .（分数：7.00）A.consume the available nutrientsB.make the oxygen balanceC.force other organisms out of riversD.overgrow and die(5).The oxidation of the decayed dead algal bodies cant _ .（分数：7.00）A.lower the amount of oxygen in the fiver waterB.make the water taste badlyC.make the water unsu

28、itable for human consumptionD.make the bacteria dead(6).What do we learn about the untreated industrial chemical wastes from the passage?（分数：7.00）A.They can conserve the normal biological action of rivers.B.They all react with water to increase the acidity of rivers.C.They make the water corrosive e

29、nough to destroy living organisms.D.There are no rules for concentrations of unquestionably toxic chemicals of drinking water.(7).What isnt said about the case with PCBs?（分数：7.00）A.An accumulation of PCBs in the human body is the direct reason of the cancer and other severe disorders.B.PCBs cant be

30、disintegrated using conventional waste-treatment ways.C.PCBs are degraded by natural processes very slowly.D.PCBs have been found in high contents in the fatty tissues of fish.(8).During the 20th century, _ , abundant conflicts in use demand, and an intensification of use that has accelerated quickl

31、y.（分数：7.00）填空项 1:_(9).Entering rivers by _ , phosphates and nitrates as fertilizers can result in eutrophication.（分数：7.00）填空项 1:_(10).That rivers are used as open sewers for city wastes causes _ and eutrophication.（分数：7.00）填空项 1:_三、Part Listening Com(总题数：0，分数：0.00)四、Section A(总题数：3，分数：105.00)Questio

32、ns 11 to 18 are based on the conversation you have just heard.（分数：56.00）A.Karen is very forgetful.B.He knows Karen better now.C.Karen is sure to pass the interview.D.The woman should have reminded Karen earlier.A.The man was sorry to miss the, football game.B.The man attended the concert, but didnt

33、like it.C.The man was sorry that he didnt attend the concert.D.The man is more interested in football than in classical music.A.Tom is very responsible.B.Toms words arent reliable.C.What Tom said is true.D.Tom is not humorous at all.A.The woman saw a horror movie.B.The woman enjoyed the movie very m

34、uch.C.The man went to the show with the woman.D.The man asked the woman to be careful at night.A.The result is what she had expected.B.The test is not well designed.C.Too few students got high marks.D.Differences between students grades are big.A.She should follow the human nature.B.Strangers are no

35、thing to be afraid of.C.Feeling nervous is nothing improper.D.She should accept strangers presents naturally.A.He agrees with the woman.B.He is a good lecturer himself.C.He is fond of Professor Smith.D.He partly agrees with the woman.A.The man couldnt find a parking lot.B.Its hard to find a place to

36、 leave the car.C.The woman was upset due to his late arrival.D.The man apologized because of his negligence.Questions 19 to 22 are based on the conversation you have just heard.（分数：28.00）A.To find out if she has the flu.B.To find out how to maintain a nutritious diet.C.To find out how to prevent ill

37、ness.D.To find out the results of a blood test.A.She gets ill at the same time every year.B.She doesnt get enough exercise.C.She often has difficulty sleeping.D.Shes sick with influenza throughout the winter.A.Shes too stressed.B.She doesnt get enough rest.C.She doesnt eat nutritious food.D.She stay

38、s in crowded places too long.A.Physical examinations are given free there.B.She can get an influenza vaccination there.C.Shell be able to get a prescription there.D.Shell find literature on nutrition there.Questions 23 to 25 are based on the conversation you have just heard. （分数：21.00）A.He was retur

39、ning home from a party.B.He just got off work when he saw the UFO.C.He was driving home from a restaurant.D.He was coming home from a police station.A.The man was out of mind.B.He drank a few beers in the party.C.He lost his directions to his home.D.He took some drugs in the party.A.They should call

40、 the fire department.B.The man should go to the party again.C.The man should contact the newspaper.D.The man should seek counseling.五、Section B(总题数：3，分数：70.00)Passage OneQuestions 26 to 28 are based on the conversation you have just heard.（分数：28.00）A.How the President proposes new laws.B.How a bill

41、is passed by lawmakers in Congress.C.How the President can reject a proposed law.D.How lawmakers can force the President to sign a bill.A.Why the President opposes a bill.B.How lawmakers want to revise a bill.C.Why a deadline has not been met.D.When lawmakers plan to end their session.A.They send th

42、e message to the President within ten days.B.They officially state reasons for rejecting the message.C.They meet with the President.D.They revise the vetoed bill.A.The bill becomes law immediately.B.The bill cant become law unless the whole process begins again.C.Lawmakers must review the bill withi

43、n ten days.D.The President must sign the bill if its passed again.Passage TwoQuestions 29 to 31 are based on the conversation you have just heard.（分数：21.00）A.To make a deal.B.To greet each other.C.To show friendliness.D.To reach an agreement.A.Westerners are unwilling to shake hands.B.Westerners are

44、 more reserved than the Chinese.C.We shouldnt shake hands with European women.D.We should make a judgment before shaking hands.A.To give us some advice before we travel abroad.B.To offer us some important facts about handshaking.C.To introduce us to some different customs in the West.D.To tell us so

45、me differences between the East and the West.Passage ThreeQuestions 32 to 35 are based on the conversation you have just heard.（分数：21.00）A.Mainly because she felt nervous on the stage.B.Mainly because she lost her interest in that role.C.Mainly because she preferred the role of the narrator.D.Mainly

46、 because she had difficulty memorizing her words.A.To remove the dandelions.B.To enjoy the garden scene.C.To have a talk with her daughter.D.To help her daughter with the play.A.Everybody has some unforgettable memory.B.Everybody should learn to play different roles.C.Everybody has his or her own va

47、lue in the world.D.Everybody can find his or her own way to success.六、Section C(总题数：1，分数：77.00)Lively argument centers around effect of public communication on audiences, not only in matters concerning public opinion on political issues, but in matters of personal life-styles and (36) , consumer beh

48、avior, the judgments and dispositions of children, and possible inducements to (37) . Feelings regarding these matters (38) greatly. Some people explain the larger effects of mass communication as generally (39) to both young and old. Many sociologists follow the theory that mass communication can i

49、nfluence values already (40) and operating in the culture. Numerous other analysts believe that mass communications provide powerful sources of informal education and persuasion. Their (41) are drawn largely from observations that many, if not most, people in technological societies form their personal views of the social realities beyond their (42) experience but from messages prese