Question

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

1. A.
   should have seen
2. B.
   might have seen
3. C.
   mustn’t have seen
4. D.
   couldn’t have seen

Answer 1

D
試題分析：句意：你昨天可能沒有見到湯姆，他上周就去國外度假去了。（1）、“must + have + 過去分詞”表示對過去發(fā)生的事情或狀態(tài)進行推測，語氣比較堅定，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 + 過去分詞”表示對過去某種情況的懷疑或不確定。can和could一般用于否定句和疑問句，could的語氣較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 + 過去分詞”表示對已發(fā)生的動作或存在的狀態(tài)進行不肯定的推測，might的語氣比may弱一點。這種結構主要用于肯定句和否定句，疑問句改用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 + 過去分詞”表示過去本該做某事但沒做，其否定式表示過去不該做某事但做了，這種句式含有不滿或責備之意，ought to的語氣比should強一些。如：
You ought to / should have studied harder. 你本應該更努力學習的。（但沒有）
He oughtn't to / shouldn't have done that. 他本來就不該做那件事。（可是做了）
考點：考查情態(tài)動詞+have done的用法
點評：情態(tài)動詞+have done是高中階段必須掌握的內容，是考生容易混淆的地方，也是考生容易失分的難點，考生應注意這方面的練習。
即學即練：Look at the time! We ______at the theatre ten minutes ago.
A.should have been    B.might have been  C.mustn’t have been D.couldn’t have been
解析：A  句意：瞧都什么時候了! 十分鐘前我們就該到戲院了。