托福句子插入题分析

　　句子插入题是托福阅读中的一种技巧性相对较强的题型。常见的类型如：举例，指代，转折/递进/事情发展顺序等逻辑关系。这里面的每一种类型在四箭齐发真题班都有覆盖，并用真题辅助练习。实际考试中，许多托福阅读29分甚至30分的同学完全凭感觉做就可以达到非常非常高的正确率。但是对于阅读达不到29分，句子插入题正确率不是特别高的同学，可以按照这个步骤训练：

　　1.首先看懂被插入的句子;

　　2.简单想想上文和下文可能讲的是什么(有时可能只能判断出上文或下文中的一者，而非两者都能判断)

　　3.看清被插入段的结构和层次，结合第二步思考的可能的上文和下文，判断何处插入合适。

　　让我们先看一道2015年1月11日托福考试的句子插入题(四箭齐发真题班课上完整讲解的一篇)

　　When some people began to settle down and produce their food through farming and animal domestication – starting about 10,000 years ago – the first epidemiological transition occurred.【】Infectious diseases increased in impact, as larger and denser concentrations of people provided greater opportunity for disease to be passed from host to host.【】Animal domestication may have brought people into contact with new diseases previously limited to other species.【】Working the soil would have exposed farmers to insects and other pathogens.【】 Irrigation in some areas provided breeding places for mosquitoes, increasing the incidence of malaria and other mosquito-borne diseases.

　　13.被插入的句子：But the denser populations of agricultural communities were only one of many factors contributing to the increased risk of disease.

　　此题比较简单，以下根据真题班讲解思路整理：

　　【分析-按照前面说的三步骤】原句说“但是，更高的人口密度不是导致疾病风险增加的唯一因素，那么前文应该讲人口密度是导致疾病风险增加的一个因素，下文讲其他因素导致疾病风险，B之前提到了人口密度对疾病传播的影响-larger and denser concentrations of people provided greater opportunity for disease to be passed from host ，B之后谈到了另外一个因素-动物的驯养-Animal domestication对疾病传播的影响。B合适。

　　再来看一道2015年2月1日的真题(四箭齐发真题班课上完整讲解的一篇)：

　　In some spiritual traditions, landscapes such as gardens or deserts were treated as abstract emblems of spiritual states such as innocence or despair.【】 Rather than symbolic landscapes, as in the Judeo-Christian tradition, Greek sacred groves operated as literal homes of the gods.【】Instead of being confined to prehistory or celestial space, spiritual parkscapes were present within the existing cultural terrain.【】One could not visit a symbol of peace and serenity, but one could experience these qualities in a sacred grove.【】

　　插入句：This, however, was not the Greek attitude.

　　【分析-按照前面说的三步骤】看懂被插入的句子This, however, was not the Greek attitude.

　　然而，这不是古希腊的 attitude.，所以，上文说的是一种非古希腊人的attitude，这句下文讲的是古希腊人的 attitude，所以这里插入这个转折句承上启下。

　　A之前讲了一种attitude(且未提及为古希腊的attitude)，A之后说古希腊如何如何，所以A合适。

　　GRE逻辑题中有许多问潜在假设和可以增强原文论证的句子的题目，而这类“增强”性质的题目，却偏偏从“削弱”性质的“反驳”入手。其实不管是GRE还是GMAT，极大一部分的逻辑题其实都是要从反驳入手的。how to attack an argument? 平时要看文章做题多想想这点(同GRE中的argument作文的思路)，然后选项就是能take care of potential attack，把潜在漏洞堵上的。也就是说，排除掉counterargument中的可能的选项的效果等同于“增强”。这就好比托福独立作文中的让步段，先承认一些问题或独立面的好处，再针对性的反驳，可以达到增强己方观点的效果。我们来看一道题

　　Cotton grass, which grows only in arctic regions, has been the only summertime source of protein available to caribou. Caribou that do not get adequate amounts of protein in the summer are unable to reproduce the following year. Rising average temperatures in arctic regions, however, are causing cotton grass to disappear. Therefore, if the warming trend continues, caribou are likely to become extinct.

　　Which of the following is an assumption on which the argument depends?

　　A. cotton grass is the only one of the caribou’s food sources that is becoming scarce as temperatures rise in arctic regions.

　　B. caribou that do not eat enough protein to reproduce do not live as long as caribou that do

　　C. The warming trend in arctic regions will not enable other plants capable of providing protein to caribou to grow there.

　　D. The caribou is the only animal that depends on cotton grass as a major source of food.

　　E. If the warming trend continues and cotton grass disappears from arctic regions, then cotton grass will be extinct.

　　分析：首先要读懂原文的逻辑，请注意一点：在现在温度下cotton grass为caribou的唯一蛋白质来源，那一种潜在反驳就是：温度变化的情况下，会不会有其他食物可以在这里生长，为caribou提供食物来源，即cotton grass不再唯一(这个很容易想到，可能其他植物在现在这么冷的环境下无法生长，而如果温度上升，可能就能生长了)，如果有其他食物，那么即便温度上升cotton grass灭绝，caribou仍然可以得以存活。而C恰恰是排除掉反驳中的这种可能性，所以是增强原文的，很明显选C。