阅读理解真题解析：Pest Control 除害虫

托福阅读理解真题解析：

Pest Control

Many pest species that are native to North America, such as white-footed mice and ground moles, are more nuisance pests and are usually regulated by native predators and parasites. 许多原产于北美的害虫种类，如白足鼠和地鼠，都是更讨厌的害虫，通常受到本地捕食者和寄生虫的控制。This situation is not true for nonindigenous pests in North America, such as brown rats and cockroaches. After centuries, it is evident that these pests cannot be eradicated. 但这种情况不适用于北美的非本土害虫，如棕鼠和蟑螂。几个世纪后，这些害虫显然无法根除。The best that can be done is to introduce pest control measures that will control their numbers.最好的办法是引入害虫控制措施来控制它们的数量。

And ancient and popular means of pest control is chemical. For example, the Sumerians used sulfur to combat crop pests, and by the early 1800s such chemicals as arsenic were used to combat insect and fungal pests.

However, chemical control has its dark side. Chemical pesticides have many unintended consequences through their effects not just on the target species but on a wide array of nontarget species as well, often eliminating them and thereby upsetting the existing food webs, especially through the suppression of native predator species. The surviving pests then rebound in greater numbers than ever.

Perhaps more insidious is that a pesticide loses its effectiveness because the target species evolves resistance to it. As one pesticide replaces another, the pests acquire a resistance to them all. [▇A] Some species, notably certain mosquitoes, have overcome the toxic effects of every pesticide to which they have been exposed. [▇B] Insect pests need not only about five years to evolve pesticide resistance, their predators do so much more slowly. [▇C] So after the pest develops resistance, pest outbreaks become even more disastrous. [▇D]

Farmer long ago observed that enemies of pests act as controls. As early as 300 C.E., the Chinese were introducing predatory ants into their citrus orchards to control leaf-eating caterpillars. Insect pests have their own array of enemies in their native habitats. When an animal or plant is introduced, intentionally or unintentionally, into a new habitat outside of its natural range, it may adapt to the new environment and leave its enemies behind. Freed from predation and finding and abundance of resources, the species quickly becomes a pest or a weed. This fact had led to the search for natural enemies to introduce into populations of pests to reduce their populations.

Because the serious pest is usually a nonnative species, biological control involves the introduction of a nonindigenous predator or parasite to control the pest. The introduction of the cactus-eating moth, a native of Argentina, into Australia effectively reduced and controlled the rapidly spreading prickly pear, which had been introduced into Australia in 1901.

But biological control, like chemical control, can backfire. The success of the cactus-feeding moth in controlling prickly pear in Australia encouraged its introduction to several West Indies islands to control prickly pear there. In time the moth made its way to Florida, where it now threatens the existence of several native prickly pear species. The moral is that although using nonindigenous predators as biological controls can be effective, these species possess their own inherent dangers that must be assessed before they are released. They, too, can become alien invaders.

Because chemical, biological, and other methods used individually are obviously not the solution to pest control, entomologists have developed a holistic approach to pest control, called integrated pest management (IPM). IPM considers the biological, ecological, economic, social, and even aesthetic aspects of pest control and employs a variety of techniques. The objective of IPM is to control the pest not at the time a major outbreak but at an earlier time, when the size of the population is easier to control. The approach is to rely first on natural mortality caused by weather and natural enemies, with as little disruption of the natural system as possible, and to use other methods only if they are needed to hold the pest below the economic injury level.

Successful IPM requires the knowledge of the population ecology of each pest and its associated species and the dynamics of the host species. It involves considerable field work monitoring the pest species and its natural enemies by such techniques as egg counts and the trapping of adults to acquire information to determine the necessity, timing, and intensity of control measures. These control measures must be adjusted to the situation, which may vary from one location to another. The intensity of control or no control is based on the degree of pest damage that can be tolerated, the costs of control, and the benefits to be derived.

1.The word “evident” in the passage is closest in meaning to

A.surprising

B.obvious

C.believed

D.frustrating

2.What can be inferred from paragraph 1 about nonindigenous pests such as brown rats and cockroaches?

A.Attempts limit the size of their populations have been unsuccessful.

B.They have inhabited North America longer than white-footed mice and ground moles.

C.Their numbers cannot usually be controlled by native predators and parasites.

D.They do not pose as many problems for humans as do white-footed mice and ground moles.

3.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A.Chemical pesticides often eliminate species other than the intended target and thereby upset food webs, especially by suppressing native predator species.

B.Native predator species are often eliminated by chemical pesticides that are intended to have consequences for other pests.

C.Chemical pesticides upset existing food webs by eliminating native species and by increasing the number of nonnative predators.

D.The effects of chemical pesticides on a wide array of food webs and native predators are often unintended.

4.According to paragraph 5, why is a species likely to become a pest when it is introduced into a new habitat?

A.The species becomes more effective at escaping from its enemies.

B.The species has no natural predators in its new habitat.

C.The species adapts to habitats outside its natural range.

D.The species does not have to compete for resources with other plants and animals.

5.In paragraph 6, the discussion of the cactus-eating moth and the prickly pear in Australia illustrates which of the following about biological control?

A.Nonnative pests cannot be controlled through biological means once they have begun to spread rapidly.

B.A nonnative pest can sometimes be controlled by the introduction of a nonnative predator.

C.A nonindigenous pest can be controlled only by a predator that comes from the same original habitat as the pest.

D.A native pest can be controlled by either a native or a nonnative predator.

6.The author discusses the cactus-feeding moth in Florida in order to

A.explain why the prickly pear species that are native to Florida have no indigenous predators

B.show how a predator spreads more rapidly in alien environments than it does in its native environment

C.indicate that a single nonindigenous predator species can be effective against a wide array of nonindigenous pest species

D.argue that controlling pests with nonindigenous predators can have unintended consequences

7.According to paragraph 8, each of the following is a principle of integrated pest management EXCEPT

A.to control pest populations before a major outbreak occurs

B.to first determine if weather and natural enemies are able to control a pest

C.to increase the populations of the pest’s natural enemies during certain seasons of the year

D.to use artificial methods of pest control only when pests begin to cause economic injury

8.According to paragraph 9, each of the following helps to determine how intensely to apply pest control measures EXCEPT

A.how much pest damage can be tolerated

B.the cost of pest control measures

C.what can be gained through pest control measures

D.whether pest control measures have been used before

9.Look at the four squares [▇] that indicate where the following sentence could be added to the passage. Where would the sentence best fit?

And the damage will continue until a new pesticide is developed, at which time the cycle will begin anew.

10.Directions:

An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This questions is worth 2 points.

A.Biological methods of pest control were introduced by the ancient Sumerians, and chemical control was first used in ancient China.

B.Biological control, for example, the use of natural enemies of pests, has been effective at regulating nonnative pests, though it can also threaten the existence of native species.

C.Integrated pest management is a holistic approach that has been successful at controlling major pest outbreaks in locations where chemical and biological control have already failed.

D.Pesticides are limited in their usefulness because pests quickly become resistant to them, and because they can harm species for which they were not intended.

E.The success of biological and chemical approaches to pest control has been difficult to measure because situations vary significantly from one location to another.

F.Integrated pest management, an approach that consider biological, ecological, economic, and aesthetic aspects of pest control, uses a variety of techniques adjusted to specific situations.

Pest Control

除害虫

文章大意：

北美本地的许多害虫物种，例如白脚老鼠和地面mole鼠，都是较有害的害虫，通常受本地食肉动物和寄生虫的控制。对于北美的非本地害虫，例如褐鼠和蟑螂，这种情况并不正确。几个世纪以来，很明显，这些害虫无法根除。最好的办法是引入害虫控制措施，以控制其数量。

而且古老而流行的害虫防治手段是化学的。例如，苏美尔人使用硫来防治农作物害虫，到1800年代初，砷等化学物质被用来防治昆虫和真菌害虫。

但是，化学控制有其阴暗面。化学杀虫剂不仅对目标物种产生影响，而且对多种非目标物种也产生许多意想不到的后果，通常会消除它们，从而破坏现有的食物网，尤其是通过抑制本地捕食者物种。幸存的害虫然后以比以往更大的数量反弹。

也许更隐蔽的是，农药会失去其功效，因为目标物种对其产生了抗药性。当一种农药替代另一种农药时，害虫对所有农药都产生了抗药性。一些物种，尤其是某些蚊子，已经克服了接触它们的每种农药的毒性作用。害虫不仅需要大约五年的时间才能发展出对杀虫剂的抗性，而且它们的掠食者这样做的速度要慢得多。因此，在有害生物产生抗药性之后，有害生物的爆发将变得更加灾难性。

农夫很久以前就观察到，害虫的敌人充当了控制者。早在公元300年，中国人就将捕食性蚂蚁引入其柑橘园，以控制食叶毛虫。害虫在其本土栖息地中有自己的敌人。将动物或植物有意或无意地引入其自然范围之外的新栖息地时，它可能会适应新环境并使其敌人落在后面。摆脱了掠夺，发现和丰富的资源，该物种迅速成为害虫或杂草。这一事实导致人们寻找天敌以引入害虫种群以减少其种群。

由于严重的有害生物通常是非本地物种，因此生物防治涉及引入非本地捕食者或寄生虫以控制有害生物。阿根廷人食用仙人掌的飞蛾传入澳大利亚有效地减少和控制了迅速蔓延的花椒，该花椒于1901年引入澳大利亚。

但是生物控制，就像化学控制一样，可能适得其反。在澳大利亚，以仙人掌为食的蛾类成功地控制了花椒，这促使它被引入了西印度群岛的一些岛屿以控制那里的花椒。随着时间的流逝，飞蛾进入了佛罗里达，现在它威胁到了几种本地花椒梨的存在。道德上是，尽管使用非土著捕食者作为生物防治措施可能是有效的，但这些物种具有其自身固有的危险，必须在释放前对其进行评估。他们也可能成为外来入侵者。

因为显然单独使用化学，生物学和其他方法不是有害生物控制的解决方案，所以昆虫学家开发了一种整体的有害生物控制方法，称为综合有害生物管理（IPM）。IPM考虑有害生物控制的生物学，生态，经济，社会乃至美学方面，并采用多种技术。IPM的目的不是在大流行时控制病虫害，而是在更容易控制种群数量的较早时候进行控制。该方法首先要依靠天气和天敌造成的自然死亡，并尽量减少对自然系统的破坏，并且仅在需要使用其他方法使有害生物保持在经济损害水平以下时才使用其他方法。

成功的病虫害综合防治需要了解每种害虫及其相关物种的种群生态学以及寄主物种的动态。它涉及大量的野外工作，通过诸如卵数计数和诱捕成虫的技术来监测害虫物种及其天敌，以获取信息以确定控制措施的必要性，时机和强度。这些控制措施必须根据具体情况进行调整，具体情况可能因一个地点而异。控制的强度或无控制的强度取决于可容忍的有害生物损害程度，控制成本以及所获得的收益。

刘凯老师解析：

1.答题解析：选B。Evident意为“明显的，显而易见的”。

2.答题解析：答案:C；对应原文After centuries, it is evident that these pests cannot be eradicated.【几个世纪后，这些害虫显然无法根除】

3.答题解析：答案:A；句子主干是Chemical pesticides have many unintended consequences through their effects.【化学杀虫剂通过其作用产生许多意想不到的后果】重点在于effects：eliminating them 和 upsetting the existing food webs. A包含了这些内容。

4.答题解析：选B。对应原文Freed from predation and finding and abundance of resources, the species quickly becomes a pest or a weed.【从捕食、寻找和丰富的资源中解脱出来，这个物种很快就变成了害虫或杂草】

5.答题解析：选B。本段主旨句Because the serious pest is usually a nonnative species, biological control involves the introduction of a nonindigenous predator or parasite to control the pest. 【由于严重的害虫通常是非本地物种，生物防治包括引入非本地捕食者或寄生虫来控制害虫】题干中所述为本段的例子，为了支持主旨句。B是本段主旨句的同义改写。

6.答题解析：选D。本段主旨句But biological control, like chemical control, can backfire. 【但是生物控制，就像化学控制，可能会适得其反】题干中“cactus-feeding moth in Florida”是支持主旨句的例子，为了论述这种生物的控制会起到反作用。本段在讨论biological control的弊端，故选D。

7.答题解析：选C。The objective of IPM is to control the pest not at the time a major outbreak but at an earlier time【IPM的目标是在更早的时间而不是在大爆发的时候控制虫害】对应A；The approach is to rely first on natural mortality caused by weather and natural enemies【这种方法首先依靠天气和天敌造成的自然死亡】对应B；to use other methods only if they are needed to hold the pest below the economic injury level.对应D。C未提及。

8.答题解析：选D。对应原文The intensity of control or no control is based on the degree of pest damage that can be tolerated, the costs of control, and the benefits to be derived.【控制的强度或不控制的程度取决于可以容忍的虫害损害程度、控制的成本和可获得的收益】只有D未提及。

9.答题解析：选D。由句中指代“the damage”，上一句应该有damage相关的内容，D位置合适。

10.答题解析：选BDF。B对应第六段主旨；D对应第三段主旨；F对应倒数第二段主旨。

刘凯老师介绍

刘凯，男，蒙古族，黑龙江省齐齐哈尔人。本科为哈尔滨师范大学英语系，硕士为北京理工大学。2010年赴美国宾夕法尼亚大学交流学习；2013年美国亚利桑那大学访问学者；2015年澳大利亚新南威尔士大学ESL研修；2018年加州理工学院语言学双学位获得者；2019年赴澳大利亚麦考瑞大学交流习；GRE托福考试全球高分获得者；荣获长江商学院EMBA。

北京市优秀青年教师，北京市级重点高中示范校骨干教师，多年高中一线执教经验，高三年级把关教师，多次参与东城区模拟试题命题工作，教学理念先进，教学成果突出，多篇教学论文获市区级奖项。多篇文章发表在《中国教育报》《中国考试》《北京教育》等报刊上。多次参加高考阅卷工作，参与人民教育出版社、北京教育出版社、外研社等各类高考教学用书的编写工作，有丰富的备考经验，国际核心期刊发表多篇论文。

教育部课题研究员，参与国家十二五课题计划，并作出突出贡献，参与初中、高中各年级区级试题的命制，多次承担区级和市级研究课任务。北京市科技英语优秀指导教师，所带学生在各级英语口语、作文竞赛中多次获奖；将扎实的英语基本功和严谨的学术思想作为教学的基础，课堂上善于寓教于乐，信息量大，内容丰富，使学生在和谐的课堂气氛下欣赏英语、享受英语、掌握英语、运用英语。

2009-2012年期间，多次受邀在北京广播电台主持英语高考大纲解析及英语新课程改革节目，学术功底深厚，兼具偶像派与实力派特点，教风亲切洒脱，诙谐幽默，思维开阔，屡有奇思妙想，善于引导学生学以致用，对高考动向把握极其准确，深受学生和家长欢迎。尤其擅长英语语法和单词记忆法。

海外生活学习十年，社科人文类学科偏爱者；10年雅思教龄，知名教师培训师；指导上万考生快速冲刺雅思写作、阅读，平均分数7.5分；独创“段落清空”、极简化“针对检索式”阅读法等众多高效技法；每年雅思考试均在10次以上；均分8+；真题回忆准确度97%以上；贴近西式思路和语言指导学生写作；善于帮助学生突破学术写作思维瓶颈。讲授科目有长难句、翻译、四六级考试、阅读和写作；在2014、2015、2017、2019四年考研中，接受其培训的所有考生中有近万名考生取得高分。带给学生的不只是考分的提高，更多的是对英语领悟和感知的突破。纯正的英音、独到的见解、睿智的思维和轻松幽默的语言，为其赢得了广大学生的认同和喜爱。

资深考研培训讲师；

英语四六级考试天团高级讲师；

雅思阅读、雅思写作培训主讲名师；

六级考试阅卷组成员；

深谙命题规律和解题套路，对英语的学习规律和方法见解独特。

呼吁国人学习英语的态度：

重复是记忆之母。

用听，用看，用心去触摸每个单词，你便会有好的记忆。

中国人要学好英语就要有一点点变态。

上课特点：课堂从不需点名，却无人缺席

教学理念：英语教师很幸运也有责任与学生一同叩响世界之门