一、推理题的标志
推理题的题干中一般含有infer, imply, most likely, least likely, probably等词，分为有共性的推理题和无共性的推理题两大类。
二、推理题的做法
对于无共性的推理题，也就是题干中无线索的，一般使用排除法，即根据各个选项的关键词回原文定位，通过排除法得出正确答案。
对于有共性的推理题，也就是题干中有线索的，可以先圈定题干中的关键词，根据关键词回原文定位，然后进行推理。推理题主要有下列思路：
1.一般对比推理
ETS设计推理题的手段不多，根据两个事物的对比特征出题是其中之一。问其中一个事物的特征时，只要将与之形成对比的另一个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?
&<61;It is not difficult to imagine what they looked like.
&<61;There were great numbers of them.
&<61;They lived in the sea only.
&<61;They did not leave many fossil remains.
根据关键词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两种动物与whales形成对比，而且很难想象原始的whales的样子;根据“一般对比推理”思路，可以推出“原始的sea otters的样子不难想象”。个选项表达了此意，为正确答案。