情態(tài)動(dòng)詞后接完成式

■表示對(duì)過(guò)去情況的推測(cè)

1. must have +P. P. 一定已經(jīng)

2. can/could have + P. P. 可能已經(jīng)

3. may/might have + P. P. 或許已經(jīng)

用例：

He must have taken the book since it isn’t here. 他一定是把書(shū)拿走了,因?yàn)闀?shū)已不在這里了。

What could have become of him now? 現(xiàn)在他可能怎么樣了呢?

You may have noted that my address has changed. 你也許已經(jīng)注意到我的地址變了。

She might have gone to have her hair waved. 她可能去燙發(fā)去了。

注意：could have done還可表示“簡(jiǎn)直就要”。如：

I could have died laughing. 我簡(jiǎn)直要笑死了。 

■表示輕微的責(zé)備或后悔

1. ought to /should + have + P. P. 本來(lái)應(yīng)該做某事(而實(shí)際上沒(méi)做)

2. ought not to /shouldn’t + have + P. P. 本來(lái)不應(yīng)該做某事(而實(shí)際上卻做了)

3. could + have + P. P. 本來(lái)能夠做某事(而實(shí)際上沒(méi)做)

4. might have +P. P. 本來(lái)可以做某事(而實(shí)際上沒(méi)做)

5. needn’t + have + P. P. 本來(lái)不必做某事(而實(shí)際上做了)

用例：

I ought to have helped her，but I never could. 我本該幫助她的，卻從未能這樣做。

They oughtn’t to have let you out of hospital so soon. 他們不應(yīng)當(dāng)讓你這樣早出院。

We all know what the poor man should have said. 我們都知道那位可憐的人兒本來(lái)應(yīng)該怎樣說(shuō)。

You shouldn’t have told him about it. 你本不該把這件事告訴他的。

She could have applied for that job, but she didn’t. 她本可以申請(qǐng)這份工作的，但她沒(méi)有。

注意：其中could, might不可用can, may代替，這與表示推測(cè)時(shí)的用法不同。