3.能作推测性用法的情态动词与所指时间

在直接引语中，情态动词无论是现在时还是过去时，也无论其后的不定式是一般式、进行式还是完成式，其所指时间几乎总是“现在”，即说话人的主观看法几乎总是以现在时间为基点的。

①情态动词+不定式一般式/不定式进行式，表示现在时间或将来时间。

②情态动词+不定式完成式，表示过去、现在完成(在间接引语中表示过去完成)。

③情态动词+不定式完成进行式，表示过去正在进行或现在完成进行。

请分析下面诸例的时间:

He must be there．=I'm sure that he is there．(一般现在时)

他一定在那里。

Our team might win the race．=It is possible that our team will win．(一般将来时)

我们队或许会赢。

He might have gone．=It is possible that he has gone(went)．(现在完成时或一般过去时)

或许他走了。

He may have come last year．=It is possible that he came last year．(一般过去时)

去年他可能来过。

They can't have been waiting so long．=I can't believe that they have been waiting so long．(现在完成进行时)

他们不可能等了这么长时间。

He must have been reading that novel last night．=I'msure that he was reading that novel last night．(过去进行时)

昨晚他一定在读那本小说。

您能用“情态动词+不定式”的适当形式改写下面句子吗?

①I don't think he is working now．

②I expect that he has heard of it now．

③Perhaps they were wondering what to do．

④I can't believe that he has lost it．

⑤I'm sure they are waiting．

⑥Perhaps she left it at home．

⑦It is possible that I was mistaken．

⑧I'm sure that a mistake has been made．

⑨It is not possible that he is there．

⑩I imagine you're been wondering all this time how it works．

答案：

①He can't be working now．

②He may have heard of it now．

③They might have been wondering what to do．

④He can't have lost it now．

⑤They must be waiting．

⑥She may/might have left it at home．

⑦I might have been mistaken．

⑧A mistake must have been made．

⑨He may not be there．

⑩You may have been wondering all this time how it works．