2016年江西成考专升本英语考试复习笔记18

　　有些情态动词，如can， could， may， might， must， ought to， should 后面可以接动词的完成形式，表示对已经发生的事的猜测或对应该发生的事的看法。

　　They shouldn’t have left so soon.

　　They must have been through a lot.

　　I needn’t have told them that.

　　He can’t have left for Shanghai for I saw him a moment ago.

　　How could you have forgotten such an important thing？

　　They must have arrived by now.

　　You oughtn’t to have done that.

　　She looks so miserable. You oughtn’t to have hurt her feelings.

　　“I was late yesterday because my car broke down. ”（broke的原型是break，这里表抛锚的意思） “You should have borrowed mine. I wasn’t using it. ”

　　情态动词部分除了应了解每个词的具体含义之外，情态动词的否定是在后面加not.特别要注意had bette和would rather的否定。ought to的否定是ought not to.would rather后面接句子只能用一般过去时。can、could、may、might、must、ought to、should后接动词完成式表示对过去事情的猜测。

　　“may/might + 现在完成时”表示“也许已经……了”；

　　“must + 现在完成时”表示“肯定……了”；

　　“can / could + 现在完成时”