However, since all the processing plants are in urban areas, removing the tariff would seriously hamper the government's effort to reduce urban unemployment over the next five years.
P:因为加工厂在城市
C:所以移除关税城市失业率会降增加
中间暗含的逻辑是：农民不卖给国内之后，加工厂要去国际市场买坚果，成本会增加，所以可能倒闭。
而这些加工厂的倒闭会引起失业率的增加。
F：imposes a high tariff on the export of unprocessed cashew nuts in order to ensure that the nuts are sold to domestic processing plants. If the tariff were lifted and unprocessed cashews were sold at world market prices, more farmers could profit by growing cashews
增加关税——因为卖到国际市场的价格是一定的，关税实际由农民承担了，所以农民profit少——农民会卖给国内，而不卖到国外
定位： the viruses themselves follow an infectious cycle in which, if protected from direct sunlight, they may remain virulent for many years in the environment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, the crystals dissolve, releasing the virus to infect the insect's cells.
C选项：allow viral DNA to be detected at low concentrations in the environment...they may remain virulent for many years in the environment, 所以不用大量，就可以是剧毒的；
定位：population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it
B选项：The passage focuses mainly on the caterpillar life stage of lepidoptera, but there is nothing to suggest that scientists held particular beliefs regarding viral diseases' restriction to that life stage.
本文需要削弱：如果不是自我调节的话，就被与此昆虫紧密相关物体，而不是鸟或寄生虫所调节。削弱它所支持的：只要找出－被鸟或寄生虫调节；或其它调节，例如habitats或是减少的人口。
A选项：无关
B选项：habitats有关
C选项：nuclear polyhedrosis virus不属于parasites of lepidoptera， 而是 an agent more intimately connected with the insect
D选项：无关
E选项：加强－病毒疾病an agent more intimately connected with the insect
but前后需要平行，while引导从句，当从句主语和主句主语相同时，从句的主语和助动词可以省略；
根据语义判断gone virtually unregulated是修饰pollutants的；
A having gone修饰不合理；
B 正确
C they存在指代歧义，指代methods,根据语义判断主语应该是industrialization and methods
D but前后不平行
E but前后不平行
定位：The common approach of studying causes of population cycles by measuring the mortality caused by different agents中studying causes of population cycles的方法
A选项：文章的主要目的是找出population circle fluctuation的原因，借助了新技术，但是不是主要目的；
B选项：并没有否定关于人口圈推动力的特殊的理论，Nuclear polyhedrosis viruses are hypothesized to be the driving force behind，指出真正的driving force;
C选项：文章的主要目的是找出population circle fluctuation的原因，提出一种假设Recent work suggests that this agent may be a virus.
D选项：文章确实提到 exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles.但是并不是作为主要写作目的，而是指出问题，然后解决问题的目的；
第一段论点：a regular pattern such as a population cycle seems to imply a dominant, driving force （control the fluctuation of population circle), 然后指出研究上很困难，has proved surprisingly elusive despite considerable research，并介绍两种方式，效果都不好。
第二段论点：提出一种假设，this agent may be a virus，然后展开假设的过程，并说明假设的依据，中途感染，怎样感染其它毛毛虫；
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定位：plants' chemical defenses against attack by herbivores such as insects