专业四级语法 | 情态动词表示推测考点归纳

1. must 和 can't 表示推测时确定程度最高,但是前者表示对事实的肯定推测,而后者表示对事实的否定推测; may 和 might 表示推测时确定程度均不高,虽然前者比后者要稍高一些,两者既可以表示对事实的肯定推测,也可以表示对事实的否定推测。例如:

  • He must be in his room now.
  • He can't be in the library now.
  • I'm not sure where he is. He may/might be in the library.
  • I don't know whether he is there. He may/might not be there.

2. 情态动词加动词原形(一般为 be )表示对现在或将来情况的推测,情态动词加动词的进行时表示对现在或将来正在发生事情的推测,情态动词加动词的完成时表示对过去发生事情的推测,情态动词加动词的完成进行时表示对过去正在发生事情的推测。例如:

  • He must be Chinese.
  • He can't be doing his homework now. He must be watching TV.
  • He must have finished his homework.
  • He can't have been doing his homework yesterday afternoon.