大学英语六级分类模拟题382

1、 大学英语六级分类模拟题 382(总分：100.00，做题时间：90分钟)一、reading comprehension(总题数：0，分数：0.00)二、(总题数：0，分数：0.00)三、(总题数：5，分数：100.00)the recent, apparently successful prediction by mathematical models of an appearance of eininothe warm ocean current that periodically develops along the pacific coast of southamericahas ex

2、cited researchers. jacob bjerknes pointed out over 20 years ago how winds mightcreate either abnormally warm or abnormally cold water in the eastern equatorial pacific.nonetheless, until the development of the models no one could explain why conditions shouldregularly shift from one to the other, as

3、 happens in the periodic oscillations between appearancesof the warm ei nino and the cold so-called anti-el nino. the answer, at least if the current modelthat links the behavior of the ocean to that of the atmosphere is correct, is to be found in theocean.it has long been known that during an el ni

4、no, two conditions exist: unusually warm water extendsalong the eastern pacific, principally alongthe coasts of ecuador and peru, and winds blow fromthe west into the warmer air rising over the warm water in the east. these winds tend to createa feedback mechanism by driving the warmer surface water

5、 into a pile that blocks the normalupwelling of deeper, cold water in the east and further warms the eastern water, thus strengtheningthe wind still more. the contribution of the model is to show that the winds of an el nino,whichraise sea level in the cast, simultaneously send a signal to the west

6、lowering sea level. accordingto the model, that signal is generated asa negative rossby wave, a wave of depressed, or negative,sea level, that moves westward parallel to the equator at 25 to 85 kilometers per day. takingmonths to traverse the pacific, rossby waves march to the western boundary of th

7、e pacific basin,which is modeled as asmooth wall but in reality consists of quite irregularisland chains, suchas, the philippines and indonesia.when the waves meet the western boundary, they are reflected, and the modelpredicts that rossbywaves will be broken into numerous coastal kelvin waves carry

8、ing the same negative sea-level signal.these eventually shoot toward the equator, and then head eastward along the equator propelledby the rotation of the earth at a speed of about 250 kilometers per day. when enough kelvin wavesof sufficient amplitude arrive from the western pacific, their negative

9、 sea-level signal overcomesthe feedback mechanism tending to raise the sea level, and they begin to drive the system intothe opposite cold mode. this produces a gradual shift in winds, one that will eventually sendpositive sea-level rossby waves westward, waves that will eventually return as cold cy

10、cle-endingpositive kelvin waves, beginning another warming cycle.（分数：20.00）(1).which of the following best describes the organization of the first paragraph?（分数：4.00）a.a model is described and its value assessed.b.a result is reported and its importance explained. c.a phenomenon is noted and its sig

11、nificance debated.d.a hypothesis is introduced and contrary evidence presented.解析：解析 推断题。根据第一段的整体结构 the recent, apparently successful prediction.hasexcited researchers.nonetheless, until the development of the models no one could explain why.分析，该段首先介绍了数学模式对厄尔尼诺现象的发生进行了成功的预测，这次预测鼓舞了研究人员。而这些数学模式发展出来之前

12、，没有人能够解释为什么这些状况发生期间出现周期性的变化。由这些分析可推知该段的逻辑顺序是先报道了一个结果，然后解释了它的重要性，和 b选项表达一致。 (2).according to the passage, which of the following features is characteristic of an el nino?（分数：4.00）a.cold coastal water near peru.b.wind blowing from the west. c.random occurrence.d.worldwide effects.解析：解析 细节题。联系第二段段首对厄尔尼

13、诺现象的解释it has long been known that during anel nino, two conditions exist: unusually warm water extends along the eastern pacific, principallyalong the coasts of ecuador and peru, and winds blow from the west into the warmer air risingover the warm water in the east. “人们早就知道，在厄尔尼诺现象发生期间，存在两种现象一是异常的暖流

14、沿着太平洋东海岸延伸，尤其是沿着厄瓜多尔和秘鲁的海岸延伸，二是从西方来的季风吹进在东方暖流中产生的更暖的空气中。”可知选项b中 winds blowing from the west“从西方来的季风”是厄尔尼诺现象的一种特征，所以答案选b。(3).which of the following, if true, would most seriously undermine the validity of the modelel nino that is presented in the passage?（分数：4.00）a.el nino extends much farther along

15、the coasts of ecuador and peru during some years.b.the rising of cold water in the eastern pacific depends on the local characters.c.the variations in the time for rossby waves to cross the pacific rely on the wind power.d.the pacific irregular western coast hinders most kelvin waves from heading ea

16、stward. 解析：解析细节题。根据第二段最后一句即花费数月时间穿越太平洋后，“罗斯比波波浪”来到太平洋盆地的西部边缘该盆地被模拟成平坦的屏障，但实际上包含很不规则的岛屿群。可知，该模式依据的是太平洋盆地的西部边缘是平坦的，而如果不是这样，则该模式就不正确。通读答案，d选项内容太平洋不规律规则的西部海岸阻碍了大多数开氏波浪流向东部和原文表述一致，所以答案选d。(4).according to the model presented in the passage, which of the following normally signals thedisappearance of an el

17、 nino?（分数：4.00）a.the arrival in the eastern pacific of negative sea-level kelvin waves. b.a shift in the direction of the winds produced by an anti-el nino.c.the reflection of kelvin waves reaching the eastern border of the pacific.d.an increase in the speed at which negative rossby waves cross the

18、pacific.解析：解析推断题。联系原文第二、三段内容，第二段介绍了厄尔尼诺现象存在的两种现象异常的暖流沿着太平洋东海岸延伸和从西方来的季风吹进在东方暖流中产生的更暖的空气中。第三段指出，如果从西部来的“开氏波浪”达到足够的量，它们就会克服提升海平面的反馈机制，促使该机制变成相反的寒冷模式，进而导致季风的逐渐转变，最终促使“罗斯比波浪”向西流动，寒冷的“开氏波浪”结束循环返回，开始另一个暖流循环。这说明，“开氏波浪”的返回就预示着厄尔尼诺现象的结束。和选项a的表述一致。(5).the primary purpose of the text as a whole is to _.（分数：4.0

19、0）a.introduce a new explanation of physical phenomenon b.explain the difference between two natural phenomenac.illustrate the limits of applying mathematics to complex problemsd.clarify the distinction between an old explanation and a new model解析：解析主旨题。回顾全文，第一段提到了利用数学模式对厄尔尼诺现象的发生进行的预测，接着介绍了该模式的重要性，第

20、二、三段具体介绍了该模式的观点。这说明，本文主要是在介绍对厄尔尼诺现象的一种新解释。所以答案选a。aided by the recent ability to analyze samples of air trapped in glaciers, scientists now havea clearer idea of the relationship between atmospheric composition and global temperature changingover the past 160,000 years. in particular, determination o

21、f atmospheric composition duringperiods of glacial expansion and retreat (cooling and warming) is possible using data from the2,000 meter vostok ice core drilled in antarctica. the technique involved is similar to that usedin analyzing cores of marine sediments, where the ratio of the two common iso

22、topes of oxygen, 180 and 160, accurately reflects past temperature changes. isotopic analysis of oxygen in thevostok core suggests mean global temperature fluctuations of up to 10 degrees centigrade overthe past 160,000 years.data from the vostok core also indicate that the amount of carbon dioxide

23、has fluctuated withtemperature over the same period: the higher the temperature, the higher the concentration ofcarbon dioxide and the lower the temperature, the lower the concentration. although change incarbon dioxide content closely follows change in temperature during periods of deglaciation, it

24、apparently lags behind temperature during periods of cooling. the correlation of carbon dioxidewith temperature, of course, does not establish whether changes in atmospheric composition causingthe warming and cooling trends or were caused by them.the correlation between carbon dioxide and temperatur

25、e throughout the vostok record is consistentand predictable. the absolute temperature changes, however, are from 5 to 14 times greater thanwould be expected on the basis of carbon dioxides own ability to absorb infrared radiation, orradiant heat. this reaction suggests that, quite aside from changes

26、 in heat-trapping gases,commonly known as greenhouse gases, certain positive feedbacks are also amplifying the temperaturechange. such feedbacks might involve ice on land and sea, clouds, or water vapor, which also absorbradiant heat.other data from the vostok core show that methane gas also correla

27、tes closely with temperatureand carbon dioxide. the methane concentration nearly doubled, for example, between the peak ofthe penultimate glacial period and the following interglacial period. within the presentinterglacial period it has more than doubled in just the past 300 years and is rising rapi

28、dly.although the concentration of atmospheric methane is more than two orders of magnitude lower thanthat of carbon dioxide, it cannot be ignored: the radiative properties of methane make it 20 timesmore effective, molecule for molecule, than carbon dioxide in absorbing radiant heat. on the basisof

29、a simulation model that climatological researchers have developed, methane appears to havebeen about 25 percent as important as carbon dioxide in the warming that took place during themost recent glacial retreat 8,000 to 10,000 years ago.（分数：20.00）(1).the primary purpose of the passage is to _.（分数：4

30、.00）a.interpret data b.explain research methodologyc.evaluate a conclusiond.suggest a new technique解析：解析 主旨题。根据文章第一、二、四段的首句 aided by the recent ability to analyze samplesof air trapped in glaciers, scientists now have a clearer idea., data from the vostok core alsoindicate that., other data from the

31、 vostok core show that.可以把握文章的主要目的是科学家通过对困在冰川中的空气样品进行分析，对大气构成与全球气温变化之间的关系进行解释说明。简而言之，就是“解释数据”，和 a选项表达一致。(2).according to the passage, which of the following statements best describes the relationshipbetween carbon dioxide and global temperature?（分数：4.00）a.carbon dioxide levels change immediately in

32、response to changes in temperature.b.carbon dioxide levels correlate with global temperature during cooling periods only.c.during cooling periods, carbon dioxide levels initially remain high and then decline. d.carbon dioxide levels increase more quickly than global temperature does.解析：解析 细节题。根据 the

33、 relationship between carbon dioxide and global temperature定位到文章第二段。although change in carbon dioxide content closely follows change in temperatureduring periods of deglaciation, it apparently lags behind temperature during periods ofcooling.“尽管在冰川消退期，二氧化碳含量的变化紧随着气温的变化，但在降温期，二氧化碳含量的变化显然滞后于气温。”说明降温期二

34、氧化碳含量先升后降，比气温下降慢一步，和选项 c表述一致，所以 c为正确答案。同时也排除了 a“二氧化碳对气温变化做出的反应是迅速的”和 b“二氧化碳含量仅在降温期和气温有关”。d“二氧化碳比气温升得更快”属于无中生有。所以答案选c。(3).the author mentions certain positive feedbacks (line 6, para.3) in order to indicate that（分数：4.00）a.increased concentration of carbon dioxide in the earths atmosphere is responsib

35、le for globaltemperature increaseb.some climate simulation models have produced useful informationc.greenhouse gases alone do not account for global temperature increase d.variables that benefit life are causing global temperature to increase解析：解析 细节题。根据第三段this reaction suggests that, quite aside fr

36、om changes inheat-trapping gases, commonly known as greenhouse gases, certain positive feedbacks are alsoamplifying the temperature change. such feedbacks might involve ice on land and sea, clouds, orwater vapor, which also absorb radiant heat. “这种关系表明，除了捕热气体(即通常所称为的温室气体)以外，某些正反馈也会扩大温度变化。此类反馈可能涉及陆地上

37、和海洋中的冰、云或水蒸气，它们也都会吸收辐射热。”可知不仅仅是温室气体导致了温度升高，某些正反馈也是原因之一，c选项和原文表述一致，所以答案选c。(4).according to the passage, which of the following statements about methane is true（?分数：4.00）a.methane is found in marine sediments.b.methane is more effective than carbon dioxide in absorbing radiant heat. c.the earths atmos

38、phere now contains more than twice as much methane as it does carbon dioxide.d.the higher the concentration of carbon dioxide in the earths atmosphere, the lower theconcentration of methane.解析：解析 细节题。根据methane定位到第四段。根据although the concentration of atmosphericmethane is more than two orders of magnit

39、ude lower than that of carbon dioxide, it cannot be ignored:the radiative properties of methane make it 20 times more effective, molecule for molecule, thancarbon dioxide in absorbing radiant heat.“尽管大气甲烷的含量要比二氧化碳的含量低两个多数量级，但它仍不能被忽视：就分子与分子相对比，甲烷的辐射特性使其在吸收辐射热这方面，要比二氧化碳强出20倍。”说明甲烷在吸收辐射热这方面比二氧化碳有效，和选项b

40、的表述一致，所以答案是b。a“甲烷是在海洋沉积物中发现的”原文没有提及，c是对原文“甲烷的含量几乎翻了一倍。在目前的间冰期范围内，它在过去短短的300年就已经增加了两倍多，并正在迅速增长”的误解，d“二氧化碳含量越高，甲烷含量越低”也没有提及。(5).the passage suggests that when the methane concentration in the earths atmosphere decreases,which of the following also happens?（分数：4.00）a.glaciers melt faster.b.the concentr

41、ation of carbon dioxide increases.c.carbon dioxide absorbs more radiant beat.d.the global temperature decreases. 解析：解析 推断题。根据文章最后一段的最后一个例子“从气候学研究者所建立的某个模拟模型来看，在8000至10000年之前的最近一次冰川稍退期间发生的升温过程中，甲烷似乎发挥了相等于二氧化碳25%的重要作用。”可知温度升高，甲烷含量升高，二者关系是正相关。那么如果甲烷含量下降，温度应该会降低，所以答案选d。one of the simplest and best known

42、 kinds of crystal is the ionic salt, of which a typical exampleis sodium chloride, or ordinary table salt. the fundamental components of an ionic salt are ions:atoms or molecules that have become electrically charged by gaining or losing one more electrons.in forming sodium chloride, for example, so

43、dium atoms give up an electron (thereby becomingpositively charged) and chlorine atoms gain an electron (thereby becoming negatively charged).the ions are attracted to one another by their opposite charges, and they stack together compactly,like tightly packed spheres. recently, scientists at michig

44、an state university created a new kind of crystal called an electride.in electrides, the anions (negative ions) are completely replaced by electrons, which are trappedin naturally formed cavities within a framework of regularly stacked cations (positive ions).electrides are the first examples of ion

45、ic salts in which all these anionic sites are occupiedsolely by electrons.unlike other types of anions, anionic electrons do not behave as if they were _simple chargedspheres . in particular, because of their low mass and their tendency to interact with one anotherover great distances, they cannot b

46、e pinned down to any one location. instead, they wander closeto and among the atoms lining the cavity and interact with electrons in nearby cavities, perhapschanging places with them.the properties of an electride depend largely on the distance between the cavities that holdtrapped electrons. when t

47、he trapped electrons are far apart, they do not interact strongly, andso behave somewhat like an array of isolated negative charges. when they are closer together,they begin to display properties associated with large ensembles of identical particles. whenthey are still closer, the ensemble properti

48、es dominate and the electrons delocalize: they areno longer tightly bound within individual cavities but are more or less flee topass through thespaces within the framework of positive ions.by synthesizing electridesfrom a variety of materials,one can vary the geometry of the anioniccavities and the

49、ir relation to the surrounding cations. the resulting properties may make itpossible for electrides to become a basis for economically useful new materials and devices. forinstance, because the electrons in some electrides are very weakly bound, these crystals couldbe effective as photosensitive det

50、ectors, in which an impinging photon liberates an electron,resulting in a small electric current. the same weak binding could also make electrides usefulin solar energy converters and as cathodes in batteries. one obstacle is the tendency of electridesto decompose through reaction with air and water

51、. researchers are seeking ways to increase theirstability.（分数：20.00）(1).the text is primarily concerned with discussing _.（分数：4.00）a.a way to isolate electronsb.the characteristics of a new kind of crystal c.the structure of an ionic saltd.commercial uses for electrides解析：解析主旨题。文章第一段讲了普通的晶体，第二段是解答本题

52、的关键，第二段中介绍了最近的科研发现电子晶体，后文都是在介绍这种新的电子晶体的特征，和 b选项表达一致。所以答案选 b。(2).in the first paragraph, the author is primarily concerned with _.（分数：4.00）a.introducing a variant on the standard atomic theoryb.describing how chlorine atoms can become negatively chargedc.providing background for the technical discuss

53、ion to follow d.describing some early research at michigan state university解析：解析推断题。根据上小题的讨论结果，文章第二段开始一直关注的是新的科研发现电子晶体，只有第一段的内容是普通的晶体，所以第一段内容是为引起下文而进行的学科普遍现象背景介绍，为后文进行铺垫，同时也和下文形成了对比。和选项 c表述一致，所以 c为正确答案。(3).according to the text, the defining characteristic of an electride is which of the following?（

54、分数：4.00）a.its positive is of particularly low mass.b.its ions possess identical electrical charges.c.it contains a framework of regularly stacked ions.d.its negative ions consist solely of electrons. 解析：解析 细节题。根据 electride定位到第二段 in electrides, the anions (negative ions) arecompletely replaced by ele

55、ctrons, which are trapped in naturally formed cavities within a framework of regularly stacked cations (positive ions). electrides are the first examples of ionicsalts in which all these anionic sites are occupied solely by electrons. “在电子晶体中，阴离子(即带负电荷的离子)全部被电子替代，这些电子被困在自然形成的空穴中，而空穴位于规则堆砌的阳离子(即带正电荷的

56、离子)的框架内。电子晶体是一种阴离子空间全被电子占据的离子盐。“可知电子晶体的阴离子完全是由电子构成的，d选项和原文表述一致，所以答案选d。(4).it can be inferred from the text that anions behaving as simple charged spheres (para.3)could be expected to _.（分数：4.00）a.readily lose electrons and become positively chargedb.move freely in and out of their cavitiesc.respond

57、to photons by liberating electronsd.remain fixed relative to their cations 解析：解析推断题。根据第三段内容，大意是“和其他类型的阴离子不同，作为阴离子的电子不像那些简单的带电球体。它们很特别，由于它们的质量很小而且有与远距离的离子进行相互作用的倾向，它们不会被固定在任何一个位置。相反，它们会到处游离，或者紧靠那些在空穴边上的原子，或者在这些原子之间游离，并且还和附近空中的电子发生相互作用，甚至还可能与它们交换位置。”可知那些简单的带电球体的阴离子会被固定，不会到处游离，和选项d的表述一致，所以答案是d。(5).with which of the following statements regarding electrides would the author most likely agree?（分数：4.00）a.they have proven themselves to be of great commercial value.b.their future commercial value is promising but uncertain. c.they are interesting but of n