一、推理題的標志

　　推理題的題干中一般含有infer， imply， most likely， least likely， probably等詞，分為有共性的推理題和無共性的推理題兩大類。

　　二、推理題的做法

　　對于無共性的推理題，也就是題干中無線索的，一般使用排除法，即根據(jù)各個選項的關鍵詞回原文定位，通過排除法得出正確答案。

　　對于有共性的推理題，也就是題干中有線索的，可以先圈定題干中的關鍵詞，根據(jù)關鍵詞回原文定位，然后進行推理。推理題主要有下列思路：

　　1.一般對比推理

　　ETS設計推理題的手段不多，根據(jù)兩個事物的對比特征出題是其中之一。問其中一個事物的特征時，只要將與之形成對比的另一個事物的特征否定掉就可以了。例如：

　　It should be obvious that cetaceans–whales， porpoises， and dolphins–are mammals. They breathe through lungs， not through gills， and give birth to live young. Their streamlined bodies， the absence of hind legs， and the presence of a fluke and blowhole cannot disguise their affinities with land-dwelling mammals. However， unlike the cases of sea otters and pinnipeds (seals， sea lions， and walruses whose limbs are functional both on land and at sea)， it is not easy to envision what the first whales looked like.

　　2. Which of the following can be inferred from paragraph 1 about early sea otters?

　　?It is not difficult to imagine what they looked like.

　　?There were great numbers of them.

　　?They lived in the sea only.

　　?They did not leave many fossil remains.

　　根據(jù)關鍵詞sea otters定位第四句：However， unlike the cases of sea otters and pinnipeds…，由原文的unlike可知sea otters和pinnipeds兩種動物與whales形成對比，而且很難想象原始的whales的樣子;根據(jù)“一般對比推理”思路， 可以推出“原始的sea otters的樣子不難想象”。第一個選項表達了此意，為正確答案。

　　2.時間對比推理

　　這種思路常被考到。在這種推理中，一般有兩個形成對比的時間段，它們所具有的特征一般相反。當題干問一個時間段的特征時，只要將與之相反的時間段的特征否定掉就可以了。

　　例一：

　　Basic to any understanding of Canada in the 20 years after the Second World War is the country’s impressive population growth….

　　…It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through the Western world since the time of the Industrial Revolution.

　　…

　　It can be inferred from the passage that before the Industrial Revolution

　　(A)families were larger.

　　(B)population statistics were unreliable.

　　(C)the population grew steadily.

　　(D)economic conditions were bad.

　　工業(yè)革命之后與工業(yè)革命之前兩個時間形成對比。既然工業(yè)革命之后西方世界的家庭變小了，那么工業(yè)革命之前的家庭一定比較大。因此(A)為正確答案。

　　例二：

　　Accustomed though we are to speaking of the films made before 1927 as “silent”， the film has never been， in the full sense of the word， silent. From the very beginning， music was regarded as an indispensable accompaniment; when the Lumiere films were shown at the first public film exhibition in the United States in February 1896， they were accompanied by piano improvisations on popular tunes. At first， the music played bore no special relationship to the films; an accompaniment of any kind was sufficient. Within a very short time， however， the incongruity of playing lively music to a solemn film became apparent， and film pianists began to take some care in matching their pieces to the mood of the film.

　　What can be inferred from the passage about the majority of films made after 1927?

　　(A) They were truly “silent.”

　　(B) They were accompanied by symphonic orchestras.

　　(C) They incorporated the sound of the actors’ voices.

　　(D) They corresponded to specific musical compositions.

　　1927年前后形成對比。既然1927年以前的電影只有音樂而沒有配音，那么1927年之后的電影一定有。所以(C)為正確答案。

　　例三：

　　“…The nineteenth century brought with it a burst of new discoveries and inventions that revolutionized the candle industry and made lighting available to all. In the early-to-mid-nineteenth century， a process was developed to refine tallow (fat from animals )with alkali and sulfuric acid. The result was a product called stearin. Stearin is harder and burns longer than unrefined tallow. This breakthrough meant that it was possible to make tallow candles that would not produce the usual smoke and rancid odor. Stearins were also derived from palm oils， so vegetable waxes as well as animal fats could be used to make candles …”

　　Which of the following can be inferred from paragraph 1 about candles before the nineteenth century?

　　?They did not smoke when they were burned.

　　?They produced a pleasant odor as they burned.

　　?They were not available to all.

　　?They contained sulfuric acid.

　　問題：關于19世紀以前的蠟燭，從第一段可以推出下列哪一點?

　　這道題的題干中有“19世紀以前”這一時間，由此可見它屬于“時間對比推理”思路。原文首句指出：“…19世紀帶來了大量新發(fā)現(xiàn)和發(fā)明，使蠟燭業(yè)發(fā)生了革命性的變化，所有人都能用蠟燭照明。” 根據(jù)“時間對比推理”思路，由于19世紀以前的情況與19世紀形成對比，而19世紀所有人能用蠟燭照明，那么在19世紀之前，并非所有人都能用上蠟燭。第三個選項 “They were not available to all”表達了這一意思，為正確答案。

　　2.集合概念推理

　　集合概念推理也可以稱之為百分比推斷，它指的是在一個集合中，包含兩個相對的方面，共同構成一個大的集合。一方所占的比例減少意味著另一方所占比例的增加;反之，一方所占的比例增加意味著另一方所占比例的減少。根據(jù)這一思路，可以由集合中一方的數(shù)量變化推斷另一方的消減。

　　例一：

　　A folk culture is small， isolated， cohesive， conservative， nearly self-sufficient group that is homogeneous in custom and race， with a strong family or clan structure and highly developed rituals. …Unaltered folk cultures no longer exist in industrialized countries such as the United States and Canada….

　　By contrast， a popular culture is a large heterogeneous group， often highly individualistic and constantly changing.

　　22.What does the author imply about the United States and Canada?

　　(A) They value folk cultures.

　　(B) They have no social classes.

　　(C) They have popular cultures.

　　(D) They do not value individualism.

　　原文談到folk culture 和popular culture兩種文化，它們之間形成對比。既然美國和加拿大不再存在folk culture，那么它們就有popular culture。因此(C)為正確答案。

　　例二：

　　Both the number and the percentage of people in the United States involved in nonagricultural pursuits expanded rapidly during the half century following the civil war， with some of the most dramatic increases occurring in the domains of transportation， manufacturing， and trade and distribution.

　　What can be inferred from the passage about the agricultural sector of the economy after the Civil War?

　　(A) New technological developments had little effect on farmers.

　　(B) The percentage of the total population working in agriculture declined.

　　(C) Many farms destroyed in the war were rebuilt after the war.

　　(D) Farmers achieved new prosperity because of better rural transportation.

　　文中指出：非農(nóng)業(yè)人口的數(shù)量和比例都增加了。由此可知農(nóng)業(yè)人口的數(shù)量和比例下降了。所以(B)為正確答案。