首先谢谢题主的邀请，在我们广大GMAT考生备考的时候，往往会对GMAT阅读部分的逻辑考点，摸不着头脑。
因为它的出题形式较为新颖，有增强或削弱结论的套路，比如Which of the following, if true, would most weaken/ strengthen the author’s conclusion in lines …? 这种题在部分情况下，会考察为结论补充前提。因此对于许多GMAT备考的考生来说，就会有一定的迷惑性。
那么这种时候我们怎么应对呢？
今天成都申友GMAT的老师就来给GMAT备考的同学们讲解，在做这类逻辑题的时候，我们正在GMAT备考中的考生应该如何应对。
首先各位GMAT考生要记住，一定要掌握一个原则，那就是无论增强结论还是削弱结论，都要回到文章中，寻找得到这个结论的前提或者相关信息，然后通过处理前提从而得到增强或者削弱结论的目的。阅读里面的逻辑题与CR的不同点就在于：我们需要下手增强和削弱的地方都是应该从文中出发寻找，不需要自己补充额外的信息，这样梳理就相对比较容易了。
所以还有一个很笨的方法教给GMAT备考的考生们，大家根据情况慎用！那就是在最下策的情况下，如果实在不知道应该怎么选，可以从选项出发，看哪个选项与文章内容最相关，这个时候选这个选项，也是相对有把握一点。
举个例子来看。
A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has proved surprisingly elusive despite considerable research. The common approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, has been unproductive in the case of lepidoptera. Moreover, population ecologists' attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar populations have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may at least be regulated by an agent more intimately connected with the insect than are predatory birds or parasites.
这是一篇GMAT阅读的第一段，针对这段考了一个逻辑题：
Which of the following, if true, would most weaken the author’s conclusion in lines “In short, … than are predatory birds or parasites.”?
(A)New research reveals that the number of species of birds and parasites that prey on Lepidoptera has dropped significantly in recent years.
(B)New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
(C)Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
(D)Differences among the habitats of Lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
(E)Viral disease is typically observed in a large proportion of the lepidoptera population.
这道题问怎么样能削弱段中的最后一句话，我们先回到文中找到这句话，里面有一个非常关键的词语In short，表明这句话是由上文得来的，得到的结论是有一个agent能影响种群周期，那么是怎么得到这个结论的呢？我们回到上文看一下。当研究种群周期的影响因素的时候，文中指出common approach是unproductive，而且进一步指出，population ecologists' attempts也是not succeeded。正是因为这两个方法都不行，我们才得到有agent的影响。那么要削弱这句话，只要表明上文的其中一个方法是可行的，那么agent就不起作用了。这个时候来看看选项，
A，讨论的是birds and parasites的数量变化，但这个变化不能说明研究方法的有效性，无关排除。
B，新的试验表明，以一种之前没有尝试过的方法改变栖息地，使得种群周期减少。这个选项影响了种群周期，而且栖息地是之前population ecologists的尝试，那么这个尝试有效了，也就不用agent了，可以削弱。
C，讨论的是NP virus数量很大，结合下文NP virus就是agent，那么自然不能削弱。
D，讨论的是天气的影响，无关排除。
E，Viral disease数量大，也是无关排除。
因此这道题应该要选B。
所以在GMAT备考中，阅读题逻辑考点应如何突破呢？相信题主还有其他备考GMAT的同学们看完本文也都能深有体会，找到突破口了，那就是GMAT阅读里的逻辑题在判断选项的时候，应该选择与结论最相关的一项。无论是增强还是削弱在文中都能找到信息对应，大家能带着这个思路做题，那么逻辑题也就能轻松攻破了。
