智哥GMAT阅读百篇精解_第20篇

智哥GMAT阅读百篇精解_第20篇

发布时间:2017-08-21 14:44:49字体: 文章来源:智哥GMAT阅读精讲

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PREP 07 Practice 2 Essay 22343

【题目纯享】

More selective than most chemical pesticides in that they ordinarily destroy only unwanted species, biocontrol agents (such as insects, fungi, and viruses) eat, infect, or parasitize targeted plant or animal pests. However, biocontrol agents can negatively affect nontarget species by, for example, competing with them for resources: a biocontrol agent might reduce the benefits conferred by a desirable animal species by consuming a plant on which the animal prefers to lay its eggs. Another example of indirect negative consequences occurred in England when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover), in turn reducing underground ant nests and triggering the extinction of a blue butterfly that had depended on the nests to shelter its offspring. The paucity of known extinctions or disruptions resulting from indirect interactions may reflect not the infrequency of such mishaps but rather the failure to look for or to detect them: most organisms likely to be adversely affected by indirect interactions are of little or no known commercial value and the events linking a biocontrol agent with an adverse effect are often unclear. Moreover, determining the potential risks of biocontrol agents before they are used is difficult, especially when a nonnative agent is introduced, because, unlike a chemical pesticide, a biocontrol agent may adapt in unpredictable ways so that it can feed on or otherwise harm new hosts.

 

Question 5

The passage is primarily concerned with

(A) explaining why until recently scientists failed to recognize the risks presented by biocontrol agents

(B) emphasizing that biocontrol agents and chemical pesticides have more similarities than differences

(C) suggesting that only certain biocontrol agents should be used to control plant or animal pests

(D) arguing that biocontrol agents involve risks, some of which may not be readily discerned

(E) suggesting that mishaps involving biocontrol agents are relatively commonplace

 

Question 6:

According to the passage, which of the following is a concern that arises with biocontrol agents but not with chemical pesticides?

(A) Biocontrol agents are likely to destroy desirable species as well as undesirable ones.

(B) Biocontrol agents are likely to have indirect as well as direct adverse effects on nontarget species.

(C) Biocontrol agents may change in unforeseen ways and thus be able to damage new hosts.

(D) Biocontrol agents may be ineffective in destroying targeted species.

(E) Biocontrol agents may be effective for only a short period of time.

 

Question 7:

The passage suggests which of the following about the blue butterfly mentioned in the highlighted text?

(A) The blue butterfly's survival was indirectly dependent on sustaining a rabbit population of a particular size.

(B) The blue butterfly's survival was indirectly dependent on sustaining large amounts of vegetation in its habitat.

(C) The blue butterfly's survival was threatened when the ants began preying on its offspring.

(D) The blue butterfly was infected by the virus that had been intended to control rabbit populations.

(E) The blue butterfly was adversely affected by a biocontrol agent that competed with it for resources.

 


 

【参考答案】:DCA

【智哥精解】

PREP 07 Practice 2 Essay 2234字,文,3个题

More selective than most chemical pesticides in that they ordinarily destroy only unwanted species, biocontrol agents (such as insects, fungi, and viruses) eat, infect, or parasitize targeted plant or animal pests. However, biocontrol agents can negatively affect nontarget species by, for example, competing with them for resources: a biocontrol agent might reduce the benefits conferred by a desirable animal species by consuming a plant on which the animal prefers to lay its eggs. Another example of indirect negative consequences occurred in England when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover), in turn reducing underground ant nests and triggering the extinction of a blue butterfly that had depended on the nests to shelter its offspring. The paucity of known extinctions or disruptions resulting from indirect interactions may reflect not the infrequency of such mishaps but rather the failure to look for or to detect them: most organisms likely to be adversely affected by indirect interactions are of little or no known commercial value and the events linking a biocontrol agent with an adverse effect are often unclear. Moreover, determining the potential risks of biocontrol agents before they are used is difficult, especially when a nonnative agent is introduced, because, unlike a chemical pesticide, a biocontrol agent may adapt in unpredictable ways so that it can feed on or otherwise harm new hosts.

 


 

【参考译文】

绝大部分化学杀虫剂更会被选择(也就是人们更愿意选择生物控制剂而不是化学杀虫剂)是因为(in that,因为)他们they指代biocontrol agents)通常会破坏只是不想要的物种,生物控制剂(比如昆虫,真菌和病毒)吃传染寄生目标植物或动物害虫但是,生物控制剂可以通过,比如与其竞争资源负面影响非目标物种;一个生物控制剂可能会通过食用某个动物喜欢去产卵(下蛋植物降低这种理想动物所赋予的利益。另外一个非直接的负面结果的例子(既然这里说是另一个间接的负面影响的例子,那前面那个例子也是间接的负面影响的例子出现在英格兰,当一个引入来控制兔子的病毒降低了裸露地的数量(因为大量的兔子降低了地被植物,反过来降低了地下的蚂蚁巢和引起一种依赖蚁巢来保护后代的蓝色蝴蝶的灭绝。已知灭绝或由于间接相互作用所导致的破坏缺乏可能反映的不是这样的灾祸的罕见,而是寻找或监测它们的失败:大部分的貌似被间接相互作用所不利影响的生物体都只有很少或未知的商业价值,并且有不利影响联系的生物控制剂的事件往往不清晰。此外被使用之间就发现生物控制剂的潜在风险是很困难的,尤其是当一个非本地的生物控制剂被引入的时候,由于,不像化学杀虫剂,一个生物控制剂用一种出乎意料的方式适应,以至于它可能会进食或者破坏新的宿主。

 


 

【文章脉络】:

生物控制只会毁掉不想要的物种,比化学杀虫剂更会被选择——但是生物控制也会对非目标物种带来负面影响——举了两个负面影响的例子——已知灭绝或破坏缺乏不是因为这样的灾祸的罕见,而是寻找或监测它们的失败——确定生物控制的风险也很困难

 

Question 5

The passage is primarily concerned with

(A) explaining why until recently scientists failed to recognize the risks presented by biocontrol agents

(B) emphasizing that biocontrol agents and chemical pesticides have more similarities than differences

(C) suggesting that only certain biocontrol agents should be used to control plant or animal pests

(D) arguing that biocontrol agents involve risks, some of which may not be readily discerned

(E) suggesting that mishaps involving biocontrol agents are relatively commonplace

主旨题。考点:

主旨(Main idea) 旨在考察我们对文章整体的把握程度,对文章的结构的分析能力和把控能力,以及对作者逻辑的判断。

这篇文章主旨明确,先陈述了生物控制好处然后提出其两个负面影响(例子),最后告诉我们生物控制剂的风险是很难察觉的。

选项分析:

(A) 解释为什么直到现在科学家们还不能识别出生物控制的风险。文中作者的确说明了生物控制剂的风险不能很好地识别,解释了不识别的一些原因,这不是作者的核心目的。

(B) 强调生物控制和化学杀虫剂的相同点多于不同点。文中主要写了生物控制的可能的不良影响,并没有说这些令生物控制和化学杀虫剂的相同多于不同。

(C) 提出只有特定的生物控制剂才能用来控制植物或害虫。作者在文中说的应该是全部的生物控制剂,并没有单提出只有某些特定生物制剂。

(D) Correct. 提出生物控制有风险,一些风险也许不能被很容易的察觉出来。考点已经详述,不再赘述。

(E) 提出关于生物控制带来的灾难相对来说是常见的。这句话“The paucity of known extinctions or disruptions resulting from indirect interactions may reflect not the infrequency of such mishaps but rather the failure to look for or to detect them”确实表明灾祸并不是不常见,但核心是想说的后面的难以发现也就是D选项。

 

Question 6:

According to the passage, which of the following is a concern that arises with biocontrol agents but not with chemical pesticides?

(A) Biocontrol agents are likely to destroy desirable species as well as undesirable ones.

(B) Biocontrol agents are likely to have indirect as well as direct adverse effects on nontarget species.

(C) Biocontrol agents may change in unforeseen ways and thus be able to damage new hosts.

(D) Biocontrol agents may be ineffective in destroying targeted species.

(E) Biocontrol agents may be effective for only a short period of time.

细节题。考点:

支持主题(Supporting ideas) 旨在考察我们对文章细节的认知

这类的题目定位比较困难,从题设来看,基本定位在全文中间的部分。

选项分析:

(A) 生物控制有可能在毁灭想要消灭的物种的同时也消灭了不想要消灭的物种。从文中的第一句可以看出,生物控制的好处就在于可以消灭特定的物种也就是说化学制剂可能会消灭掉其它不应该被消灭的物种。后文有提到说,生物控制也可能会对不想要的物种产生负面影响。所以,这点不是两者的不同点更多是相同点。

(B) 生物控制有可能用直接的和非直接的影响在非目标生物上。从文中可以看出,生物控制不能直接影响非目标生物而是非直接的影响,原文举的例子也都是indirect consequence

(C) Correct. 生物控制可能会有不可预见性的改变并且有能力毁掉新的物种。这个选项定位在“especially when a nonnative agent is introduced, because, unlike a chemical pesticide, a biocontrol agent may adapt in unpredictable ways so that it can feed on or otherwise harm new hosts.”。几乎是原文的直译而且unlike chemical pesticide,很明显就是生物控制剂所拥有化学杀虫剂所没有的

(D) 生物控制可能会对想要消灭的物种无效。文中没有讨论消灭目标物种的有效性问题。

(E) 生物控制可能只在段时间内有效。文中没有提到生物控制是否长期有效。

 

Question 7:

The passage suggests which of the following about the blue butterfly mentioned in the highlighted text?

(A) The blue butterfly's survival was indirectly dependent on sustaining a rabbit population of a particular size.

(B) The blue butterfly's survival was indirectly dependent on sustaining large amounts of vegetation in its habitat.

(C) The blue butterfly's survival was threatened when the ants began preying on its offspring.

(D) The blue butterfly was infected by the virus that had been intended to control rabbit populations.

(E) The blue butterfly was adversely affected by a biocontrol agent that competed with it for resources.

细节题。考点:

推断(Inference) 旨在考察我们对文章的深度理解,以及逻辑推断能力。

这个题目定位在高亮词的地方Another example of indirect negative consequences occurred in England when a virus introduced to control rabbits reduced the amount of open ground (because large rabbit populations reduce the ground cover), in turn reducing underground ant nests and triggering the extinction of a blue butterfly that had depended on the nests to shelter its offspring.

选项分析:

(A) Correct. 蓝色蝴蝶的生存依赖于兔子的数量维持在一定的水平。定位句说蓝蝶依赖于蚁巢生存(保护后代),而蚁巢降低是由于兔子降低导致open ground后所导致的,所以blue butterflyrabbit数量有关。

(B) 蓝色蝴蝶的生存依赖于在其栖息地维持大量的植被。从定位句可以看出,蓝蝶依赖于蚁巢(来保护蓝蝶后代蚁巢的植被,而不是蓝蝶的栖息地的植被。

(C) 蓝蝶的生存在蚂蚁开始捕食蓝蝶的后代时受到了威胁。文中没有提到蚂蚁会捕食蓝蝶后代

(D) 蓝蝶感染了用来控制兔子数量的病毒。文中没有提到蓝蝶感染病毒。

(E) 蓝蝶被生物控制剂带来负面影响是这些生物控制剂与蓝蝶竞争资源。文中定位部分说的很清楚,和生物控制剂是否与它们抢夺资源无关。

 


 

【智哥点评】:这篇文章并不长,但理解起来肯定有一定难度,毕竟是生物类的文章,相对生僻。原文的“专业知识不见得能读懂,但文章整体逻辑还是比较清楚的,而且并没有考最难懂的原理部分,考点应该只会出在考生应该能看懂地方,值得各位G友多体会。

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