解答推理题应从识别题型入手。推理题题干中常见表示推理或暗示的词汇：infer，imply，indicate，suggest。下面小编就和大家分享托福阅读推理题的对比取反情况，希望能够帮助到你们，快来一起学习吧。

托福阅读推理题的对比取反情况

1. Paragraph: Two other developments presaged the end of the era of turnpikes and started a transportation revolution that resulted in increased regional specialization and the growth of a national market economy. First came the steamboat; although flatboats and keelboats continued to be important until the 1850s, steamboats eventually superseded all other craft in the carrying of passengers and freight. Steamboats were not only faster but also transported upriver freight for about one tenth of what it had previously cost on hand-propelled keelboats.

1. Which of the following can be inferred from the paragraph about flatboats and keelboats?

A. They ceased to be used as soon as the first turnpikes were built.

B. They were slower and more expensive to operate than steamboats.

C. They were used for long-distance but not for regional transportation.

D. They were used primarily on the Erie Canal.

根据题干信息flatboats and keelboats对应到原文句子Steamboats were not only faster but also transported upriver freight for about one tenth of what it had previously cost on hand-propelled keelboats. 从句子里steamboat以及keelboats之间的faster 以及one tenth of很容易得出B选项。解出答案之后，希望大家思考，这样一道推理题透露了出题人设置题目时的逻辑思维，那就是信息的对比，而且有对比的时候，答案往往会取反面。

2. Paragraph: A symbiotic relationship is an interaction between two or more species in which one species lives in or on another species. There are three main types of symbiotic relationships: parasitism, commensalism, and mutualism. The first and the third can be key factors in the structure of a biological community – that is, all the populations of organisms living together and potentially interacting in a particular area.

1. Which of the following statements about commensalism can be inferred from the paragraph?

A. It excludes interactions between more than two species.

B. It makes it less likely for species within a community to survive.

C. Its significance to the organization of biological communities is small.

D. Its role in the structure of biological populations is a disruptive one.

根据题干信息commensalism对应到原文句子There are three main types of symbiotic relationships: parasitism, commensalism, and mutualism.该句得不出答案，接着看到The first and the third can be key factors in the structure of a biological community;该句告诉我们first and third指代上句中的parasitism和mutualism, 而题干中被问及的commensalism(共栖)恰是三者之中剩余的部分，根据例一中出题人对于对比取反的逻辑设置，显然该题同样取反，既然文中给出一三重要，那么强烈暗示的就是处于第二的commensalism不重要，所以选C。

3. Paragraph: Isotopic analysis of shells allowed geologists to measure another glacial effect. They could trace the growth and shrinkage of continental glaciers, even in parts of the ocean where there may have been no great change in temperature – around the equator, for example. The oxygen isotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice. During glaciations, the lighter oxygen-16 has a greater tendency to evaporate from the ocean surface than the heavier oxygen-18 does. Thus, more of the heavy isotope is left behind in the ocean and absorbed by marine organisms. From this analysis of marine sediments, geologists have learned that there were many shorter, more regular cycles of glaciation and de-glaciation than geologists had recognized from the glacial drift of the continents alone.

1. It can be inferred from paragraph 5 that foraminifera fossil shells containing calcite with high percentages of oxygen-16 were deposited at times when…

A. polar ice extended as far as equatorial regions of land and sea.

B. extensive glaciation was not occurring.

C. there were no great increases in ocean temperature.

D. there was heavy snowfall on continental glaciers.

同样根据题干信息oxygen-16对应到原文During glaciations, the lighter oxygen-16 has a greater tendency to evaporate from the ocean surface than the heavier oxygen-18 does. 句中给出during glaciations的时候oxygen-16会蒸发离开，题干问什么时候oxygen-16 were deposited, 同样还是对比取反，即not during glaciations，对应选项B。

4. Paragraph 2: The areas covered by this material were so vast that the ice that deposited it must have been a continental glacier larger than Greenland or Antarctica. Eventually, Agassiz and others convinced geologists and the general public that a great continental glaciation had extended the polar ice caps far into regions that now enjoy temperate climates. For the first time, people began to talk about ice ages. It was also apparent that the glaciation occurred in the relatively recent past because the drift was soft, like freshly deposited sediment. We now know the age of the glaciation accurately from radiometric dating of the carbon-14 in logs buried in the drift. The drift of the last glaciation was deposited during one of the most recent epochs of geologic time, the Pleistocene, which lasted from 1.8 million to 10,000 years ago. Along the east coast of the United States, the southernmost advance of this ice is recorded by the enormous sand and drift deposits of the terminal moraines that form Long Island and Cape Cod.

1. It can be inferred from paragraph 2 that Agassiz and other geologists of his time were not able to determine…

A. which geographic regions had been covered with ice sheets in the last ice age.

B. the exact dates at which drifts had been deposited during the last ice age.

C. the exact composition of the drifts laid during the last ice age.

D. how far south along the east coast of the United States the ice had advanced during the last ice age.

通过以上的例子，相信大家已经熟悉了推理题中对比取反的逻辑思维。那么最后这一道题，是否能够应用讲解的规律顺利得出正确答案呢?

首先读题干，很多考生会选择Agassiz and other geologists这一信息去对应原文，结果发现无法根据文中对应信息得出正确答案。此时要牢记对比取反的逻辑思维，重新审题发现了of his time这一时间短语与文中的We now know the age of the glaciation accurately from radiometric dating of the carbon-14 in logs buried in the drift.一句里的now构成对比关系。所以根据对比取反的逻辑，既然我们现在才精确知道冰川形成的时间，那么在当时是不知道的，顺利选出B选项。

托福阅读长难句：嗅觉交流

The importance of olfactory communication (using odors to communicate) in the way of life of deer was documented by a study of captive adult male deer a few decades ago, which noted that males rubbed their foreheads on branches and twigs, especially as autumn approached. (TPO28, 45)

olfactory /ɒl'fækt(ə)rɪ/ adj. 嗅觉的

document /'dɒkjʊm(ə)nt/ vt. 用文件证实或证明(某事)

captive /'kæptɪv/ adj. 被捕获的，被俘虏的

twig /twɪg/ n. 嫩枝

approach /ə'prəʊtʃ/ vt. 接近, 靠近

The importance (of olfactory communication) (using odors to communicate) (in the way of life of deer) was documented (by a study of captive adult male deer a few decades ago), (which noted)(that males rubbed their foreheads on branches and twigs), (especially as autumn approached). (TPO28, 45)

分析：

这个句子的主干就是：

The importance was documented

修饰一：(of olfactory communication)，介词短语

中文：嗅觉交流

修饰二：(using odors to communicate)，非谓语动词

中文：使用气味去交流

修饰三：(in the way of life of deer)，介词短语

中文：在鹿群生活方式中

修饰四：(by a study of captive adult male deer a few decades ago)，介词短语

中文：一个关于被捕获的成年雄鹿的研究

修饰五：(which noted)，从句

中文：研究提到

修饰六：(that males rubbed their foreheads on branches and twigs)，从句

中文：雄鹿会在树枝和嫩枝上摩擦前额

修饰七：(especially as autumn approached)，从句

中文：尤其当秋天临近时

参考翻译：

嗅觉交流(使用气味去交流)在鹿群生活方式中的重要性，被几十年前一个关于被捕获的成年雄鹿的研究证实，这个研究提到：尤其当秋天临近时，雄鹿会在树枝和嫩枝上摩擦前额。

托福阅读长难句：释放水动能

They revealed output powers ranging from about 1 horsepower to perhaps 60 for the largest wheels and confirmed that for maximum efficiency, the water should pass across the blades as smoothly as possible and fall away with minimum speed, having given up almost all of its kinetic energy. (TPO29, 48)

blade /bleɪd/ n. (刀﹑ 剑﹑ 凿等的)刃;(划水桨﹑ 螺旋桨﹑ 锹﹑ 铲﹑ 板球击球板等的)扁宽平面部分

kinetic /kɪ'netɪk/ adj. 运动的，运动引起的

They revealed output powers (ranging from about 1 horsepower to perhaps 60) (for the largest wheels) and confirmed that (for maximum efficiency), the water should pass across the blades as smoothly as possible and fall away with minimum speed, (having given up almost all of its kinetic energy).(TPO29, 48)

分析：

这个句子主干就是：

They revealed output powers and confirmed that

宾语从句的主干：the water should pass across the blades as smoothly as possible and fall away with minimum speed

中文：水应该从叶轮上尽可能光滑地流过，并以最小的速度流走

修饰一：(ranging from about 1 horsepower to perhaps 60)，非谓语动词

中文：输出功率范围是从1马力到最大水轮可能输出的60马力

修饰二：(for the largest wheels)，介词短语

中文：对于最大水轮

修饰三：(for maximum efficiency)，介词短语

中文：为了达到最高效率

修饰四：(having given up almost all of its kinetic energy)，非谓语动词

中文：释放水的几乎所有动能

参考翻译：

它们(调查)显示输出功率范围是从1马力到最大水轮可能输出的60马力;它们也确定了要达到最高效率，水应该从叶轮上尽可能光滑地流过，并以最小的速度流走，释放水的几乎所有动能。