Question

You____Tom at the party yesterday;he went abroad for a holiday last week.

A．should have seen	B．might have seen
C．mustn’t have seen	D．couldn’t have seen

Answer

D

【解析】

试题分析：句意：你昨天可能没有见到汤姆，他上周就去国外度假去了。（1）、“must + have + 过去分词”表示对过去发生的事情或状态进行推测，语气比较坚定，通常只用于肯定句。如：

It must have rained last night, for the ground is wet. 

You must have been mad to speak to the servant. 

（2）、“can / could + have + 过去分词”表示对过去某种情况的怀疑或不确定。can和could一般用于否定句和疑问句，could的语气较can弱。如：

I didn't see her at the meeting this morning; she can't / couldn't have spoken at the meeting.

He can't have finished the work so soon. 

（3）、“may / might + have + 过去分词”表示对已发生的动作或存在的状态进行不肯定的推测，might的语气比may弱一点。这种结构主要用于肯定句和否定句，疑问句改用can或could。如：

They may not have known it beforehand.

You might have read about it in the papers.

（4）、“should / ought to + have + 过去分词”表示过去本该做某事但没做，其否定式表示过去不该做某事但做了，这种句式含有不满或责备之意，ought to的语气比should强一些。如：

You ought to / should have studied harder. 你本应该更努力学习的。（但没有）

He oughtn't to / shouldn't have done that. 他本来就不该做那件事。（可是做了）

考点：考查情态动词+have done的用法