托福考試的閱讀推理題分為有共性和無共性的推理題。

有共性的推理題是指在題目中有若干線索，考生可以先圈定題幹中的相關關鍵詞，之後再根據關鍵詞回原文定位，然後進行推理。

推理題的兩大分類：有共性的推理題和無共性的推理題。這裡所謂的有共性推理題就是說題幹中有和原文內容相同的關鍵詞(也叫線索)。根據關鍵詞回原文定位，然後進行推理。一般來說，大多數的推理題都屬於這類題目。對於無共性的推理題，也就是題幹中無線索，一般使用排除法，即根據各個選項的關鍵詞回原文定位，透過排除法得出正確答案。返回原文找資訊點，採用排除法是解決這兩類題型解決的共同策略。

推理題大概有三個解題思路：一般對比推理、時間對比推理、集合概念推理。一般對比推理：根據兩個事情的對比特徵，問其中一個事物的特徵，只要將與之形成對比的另外一個事情的特徵否定掉就可以。時間對比推理：在這種推理中，一般有兩個形成對比的時間段，它們所具有的特徵一般相反。當題幹問一個時間段的特徵時，只要將與之相反的時間段的特徵否定掉就可以了。集合概念推理 ：一個大的集合的兩個方面形成對比，兩者之間存在著互補性關係，也就是一個的增加意味著另一個的減少。反之，相同。

在這裡我們先來看一個例子： Passage：…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?a.They did not smoke when they were burned.b.They produced a pleasant odor as they burned.c.They were not available to all.d.They contained sulfuric acid.

正確答案是C.這一段的第一句就告訴我們：19世紀的一些新發明和發現也對蠟燭工業產生了一次巨大的革命，這次革命使得所有的人都使用上了照明。從這句話中我們可以得到兩層資訊：19世紀蠟燭工業有了一次革命性的變化;在沒有這次變革之前，也就是在19世紀以前，照明並不是所有人都能使用的。因為作者在談論的是蠟燭的變革，所以這裡所說的“lighting照明”一定是與蠟燭有關的照明，其實也就是告訴我們19世紀以前並不是所有人都能夠使用到蠟燭帶來的照明，這一推論出的資訊正好與選項C吻合。文章第一句同時也是一個時間的分水嶺，告訴我們19世紀蠟燭工業的變革是怎麼樣的。“在19世紀早期到中期，蠟燭處理工藝使用alkali 和 sulfuric acid 來提煉 tallow，提煉後的產品就是 stearin，stearin 比未經提煉的tallow堅硬而且燃燒得更久。這一巨大的變化意味著製造出不產生煙和rancid味道的蠟燭是可能的。”在這裡的一個關鍵詞是 rancid，意思是(油脂食物，其味道、氣味)不新鮮的;腐臭的;正好與選項b的pleasant odor相反。19世紀前的蠟燭產生usualsmoke(經常有煙)，這與選項a相反。Sulfuric acid是19世紀用來處理fallow的材料，在19世紀以前是沒有使用的，這與選項d相反。

解答這類題目時要注意這些關鍵資訊點：日期和數字、關鍵詞： 表示多少的副詞: many , some, much of, several , a few ,most …;情態動詞：may, can , could…;表示過去的：used to be , was, were , at one time, previously ;表示不是唯一的： not only ,not exclusively等。在此，我們再來看一道例題：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 fluke3 and blowhole4 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. Extinct but, already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.Which of the following can be inferred from paragraph 1 about early sea otters?a. It is not difficult to imagine what they looked likeb.There were great numbers of them.c. They lived in the sea only.d.They did not leave many fossil remains.首先我們來對題目的出題範圍進行定位，題乾的blowhole可以作為定位詞彙，定位到原文的第四句話：“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.” 在這句話裡交代了“unlike the casess of sea otters”，即與sea otters 不一樣的是，whales 的陳述是：it is not easy to envision what the first whales looked like. 即，不容易看出第一頭鯨長什麼樣子。而sea ottter 是和鯨魚相反，所以選擇A選項，即不難看出第一頭sea otter 長什麼樣子。所以實際上，這種題目雖然叫做推理題，但是並不需要同學們在做題的時候推的過遠，基本考察的還是對原文資訊概括和總結的能力。