人教高考英语二轮复习：说明类完形填空学案（含答案）.docx

说明类完形填空
说明文一般用言简意赅的文字，按照一定的方法介绍事物，解释事理。其最显著的特点是:开头点题，结构条理清晰。考生做题的关键在于理清文章结构，把握全文大意。
 常见、常考的说明文集中在阐述事理、方法（步骤）介绍，产品说明、实验报告、科普小品等。这类文章主要的特点：
  1. 开头点题
  2. 篇章的条理清晰、层次分明
 说明文层次分明，脉落清晰，有条有理。大多数完形填空的说明文是按因果关系进行说明，有的按先主后次的顺序进行说明，有的先概述后举例，有的先举例后概述，也有的按事情的逻辑关系来展开。
题例
( 2013广东卷）
    Number sense is not the ability to count. It is the ability to recognize a    1    in number. Human beings are born with this ability.  2  ，experiments show that many animals are, too. For example, many birds have good number sense. If a nest has four eggs and you remove one, the bird will not   3  .However, if you remove two, the bird  4  leaves. This means that the bird knows the   5   between two and three.
    Another interesting experiment showed a bird's  6  number sense. A man was    trying to take  a photo of a crow(乌鸦)that had a nest in a tower, but the crow always left when she saw him coming. The bird did not  7  until the man left the tower. The man had an  8  .He took another man with him to the tower. One man left and the other stayed, but they did not  9   the bird. The crow stayed away until the second man left, too. The experiment was   10  with three men and then with four men. But the crow did not return to the nest until all the men were  11 .It was not until five men went into the tower and only four left that they were  12  able to fool the crow.
How good is a human's number se