考前冲刺:2021年考研英语阅读经典试题及答案(十八)

发布时间:2020-10-10


英语是考研初试当中比较拉分的科目,历来令不少考生又爱又恨。许多考生的英语都有很大的进步空间,因此英语该如何学就成为了众多考生关心的重点。想要学习英语,实战经验很重要。下面,51题库考试学习网为大家带来考研初试英语科目的一些模拟试题,正在备考的小伙伴赶紧练起来吧。

Although recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing. Consequently, more than 100 cities in the United States still have levels of carbon monoxide, particulate matter, and ozone (generated by photochemical reactions with hydrocarbons from vehicle exhaust) that exceed legally established limits. There is a growing realization that the only effective way to achieve further reductions in vehicle emissions short of a massive shift away from the private automobile is to replace conventional diesel fuel and gasoline with cleaner-burning fuels such as compressed natural gas, liquefied petroleum gas, ethanol, or methanol.

All of these alternatives are carbon-based fuels whose molecules are smaller and simpler than those of gasoline. These molecules burn more cleanly than gasoline, in part because they have fewer, if any, carbon-carbon bonds and the hydrocarbons they do emit are less likely to generate ozone. The combustion of larger molecules, which have multiple carbon-carbon bonds involves a more complex series of reactions. These reactions increase the probability of incomplete combustion and are more likely to release uncombusted and photochemically active hydrocarbon compounds into the atmosphere. On the other hand, alternative fuels do have drawbacks. Compressed natural gas would require that vehicles have set of heavy fuel tanks a serious liability in terms of performance and fuel efficiency and liquefied petroleum gas faces fundamental limits on supply.

Ethanol and methanol, on the other hand, have important advantages over other carbon-based alternative fuels: they have higher energy content per volume and would require minimal changes in the existing network for distributing motor fuel. Ethanol is commonly used as a gasoline supplement, but it is currently about twice as expensive as methanol, the low cost of which is one of its attractive features. Methanols most attractive feature, however, is that it can reduce by about 90 percent the vehicle emissions that form ozone, the most serious urban air pollutant.

Like any alternative fuel, methanol has its critics. Yet much of the criticism is based on the use of gasoline clone vehicles that do not incorporate even the simplest design improvements that are made possible with the use of methanol. It is true, for example, that a given volume of methanol provides only about one-half of the energy that gasoline and diesel fuel do; other things being equal, the fuel tank would have to be somewhat larger and heavier. However, since methanol-fueled vehicles could be designed to be much more efficient than gasoline clone vehicles fueled with methanol they would need comparatively less fuel. Vehicles incorporating only the simplest of the engine improvements that methanol makes feasible would still contribute to an immediate lessening of urban air pollution.

1. The author of the text is primarily concerned with

[A] countering a flawed argument that dismisses a possible solution to a problem.

[B] reconciling contradictory points of view about the nature of a problem.

[C] identifying the strengths of possible solutions to a problem.

[D] discussing a problem and arguing in favor of one solution to it.

2. According to the text, incomplete combustion is more likely to occur with gasoline than with an alternative fuel because

[A] the combustion of gasoline releases photochemically active hydrocarbons.

[B] the combustion of gasoline embraces an intricate set of reactions.

[C] gasoline molecules have a simple molecular structure.

[D] gasoline is composed of small molecules.

3. The text suggests which of the following about air pollution?

[A] Further attempts to reduce emissions from gasoline-fueled vehicles will not help lower urban air-pollution levels.

[B] Attempts to reduce the pollutants that an individual gasoline-fueled vehicle emits have been largely unsuccessful.

[C] Few serious attempts have been made to reduce the amount of pollutants emitted by gasoline-fueled vehicles.

[D] Pollutants emitted by gasoline-fueled vehicles are not the most critical source of urban air pollution.

4. Which of the following most closely parallels the situation described in the first sentence of the text?

[A] Although a town reduces its public services in order to avoid a tax increase, the towns tax rate exceeds that of other towns in the surrounding area.

[B] Although a state passes strict laws to limit the type of toxic material that can be disposed of in public landfills, illegal dumping continues to increase.

[C] Although a towns citizens reduce their individual use of water, the towns water supplies continue to dwindle because of a steady increase in the total populating of the town.

[D] Although a country attempts to increase the sale of domestic goods by adding a tax to the price of imported goods, the sale of imported goods within the country continues to increase.

5. It can be inferred that the author of the text most likely regards the criticism of methanol as

[A] flawed because of the assumptions on which it is based.

[B] inapplicable because of an inconsistency in the critics arguments.

[C] misguided because of its exclusively technological focus.

[D] inaccurate because it ignores consumers concerns.

参考答案及解析

1.【答案】C

【考点解析】这是一道中心主旨题。本文的中心主旨句是首段的尾句。通过对首段尾句以及其它段落主题句的阅读和理解,可以推导出本题的正确选项是C。考生在破解此类题型时一定要首先抓住原文的中心主旨句以及各段的主题句。

2.【答案】B

【考点解析】本题是一道指代词题型。根据题干中的“incomplete combustion”可将本题的答案信息来源迅速确定在第二段的第四句,该句中的指代词“these”暗示本题的具体答案信息来源应该在第二段的第三句。通过阅读和理解第二段的第三句可推导出本题的正确选项是B。考生在解题时对指代词一定要认真理解。

3.【答案】A

【考点解析】本题是一道审题定位题型。通过题干中的“air pollution”可将本题的答案信息来源迅速确定在第一段,因为第一段首句中含有“noxious pollutants”,都在谈污染的问题。通过阅读和理解第一段,尤其是第一段尾句即全文的中心主旨句,可推导出本题的正确选项是A。这是一道比较难的题。考生在解题时一定要具备审题定位能力,还要具备归纳和推导能力。

4.【答案】C

【考点解析】这是一道类比题型,因为本题题干中含有“parallels(与……相当,与……一样)一词。本题题干已将类比的参照对象确定在第一段的首句。通过仔细阅读和理解第一段的首句,可推导出本题的正确选项是C,因为该选项涉及的增减关系的前提条件和原文一脉相承。考生在破解这种题型时应对原文所表达的内容与关系有明确的认识和把握,不可以无根据地推导。

5.【答案】A

【考点解析】这是一道细节推导题型。本题题干中的“the criticism of methanol”把本题的答案信息来源确定在第四段的第一、二句。通过阅读和理解这两句话,尤其是第二句话,就可推导出本题的正确选项A。考生在破解本题时一定要注意第二句话的第一个词“Yet”在语意上所起的作用。考生在解题时一定要重视启承转合词的出现和功能。

以上就是51题库考试学习网为大家带来的全部内容,希望能给大家一些帮助。51题库考试学习网提醒:在最后阶段,调整自己的心态也是非常重要的,每年都有考生临考前放弃,所以小伙伴们要注意不要给自己太大的压力哦。另外,小伙伴们如果还有其他关于考研信息的疑问,也可以留言咨询哦。


下面小编为大家准备了 研究生入学 的相关考题,供大家学习参考。

作家史铁生在《奶奶的星星》中讲道,奶奶告诉他的故事与通常的说法不同:一般人说,地上 死一个人,天上就熄灭了一颗星星;而奶奶说,地上死一个人,天上又多了一个星星,人死了 就会升到天空,变成星星给走夜道的人照个亮了。于是他“慢慢相信,每一个活过的人,都能 给后人的路途上添些光亮,也许是一颗巨星,也许是一把火炬,也许只是一支含泪的烛 光……”这对我们理解个人在社会历史中的作用的启示有

A.杰出个人决定历史发展的走向
B.人人都是历史的创造者
C.历史是无数个人相互作用的合力的结果
D.每个人对社会发展都有或大或小的作用
答案:C,D
解析:
本题考查的知识点是人民群众是历史的创造者与个人在社会历史中的作用,属于理解性试题。人民群众是历史的创造者,而不是杰出个人创造历史,所以A是错误选项;人民群众从质上说是指一切对社会历史发展起推动作用的人们,从量上说是指社会人口中的绝大多数,人民群众不等同于人人,所以不能说人人创造历史,故B选项错误;社会历史发展是无数个人合力作用的结果,C选项是正确选项;D选项“每个人对社会发展都有或大或小的作用”也是正确表述。所以正确选项是CD。

参苓白术散的君药是

A.白茯苓
B.人参
C.白术
D.山药
答案:A,B,C
解析:
参苓白术散主治:脾虚湿盛证,因虚所致,故应以补虚为主,脾气健运,湿邪自化。所以参苓白术散的君药是人参、白术、茯苓益气健脾渗湿,四君子汤是治疗脾虚的基本方。

视杆细胞感受器电位的特点是

A.局部电位 B.去极化慢电位 C.超极化慢电位 D.去极化快电位

答案:C
解析:
视杆细胞的感受器电位是光线刺激时,Na+内流减少形成的一种超极化慢电位,并不是去极化 型慢电位。

冈崎片段是指
A.复制起始时,RNA聚合酶合成的片段
B.两个复制起始点之间的DNA片段
C.DNA半不连续复制时出现的DNA片段
D.DNA连续复制时出现的DNA片段
E. E. coli复制起始点oriC的跨度为245bp的片段

答案:C
解析:
①由于DNA的复制是半不连续复制,复制叉前进的方向与领头链的合成方向相同。领头链的 子链沿方向连续延长,其延长方向与解链方向相同。随从链的子链延长方向与解链方向相反,需 要等待复制叉解开足够长度,生成新的引物,然后再在引物3’-OH末端上延长。也就是说,领头链连续复 制而随从链不连续复制,这就是复制的半不连续性。随从链上不连续的片段称为冈崎片段。复制 完成后,这些不连续片段经过去除引物,填补引物留下的空隙,连成完整的DNA链。②E.coli上有一固 定的复制起始点,在82分钟位点上,称oriC。oriC的跨度为245bp。

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