1、情態(tài)動詞的完成式
1)must have done——表示對過去的事情較有把握的、肯定性的推測,常譯為“一定,準是,肯定”,其否定形式是can’t/couldn’thave done,意為“決不可能,不太可能”。
e.g. Since the ditch is full of water, it must have rained last night.
2)should/ought to have done——表示過去應(yīng)該做的卻沒有做,常含有后悔、責備、埋怨的口吻,意為“本應(yīng)該”,“應(yīng)該就好了”; e.g. With all the work finished, I should have gone to your birthday party last night.
3)shouldn’t/ought not to have done——表示過去不該做的事卻給做了,也常含有責備、不滿之意,意為“本不該”。
e.g. You shouldn’t have gone back to work yesterday without the doctor’s permission.
4)may/might have done——表示對過去的事情的推測,但不十分有把握,意為“可能,或許已經(jīng)”。 e.g. A traffic accident happened yesterday and a driver may have been hurt.
5)could have done——表示過去有可能或有能力做某事,而實際未做、未能實現(xiàn)的事;有時也表示輕度批評,意為“本來可以,完全可以”。 e.g. The gas leakage could have been avoided if the gas company took immediate measures after the warning call.
6)needn’t have done——表示過去做了某事,但沒有做的必要,意為“其實沒有必要”。 e.g. I needn’t have bought all that wine——only three people came.
2、可作情態(tài)動詞用的短語
would rather, would sooner, would (just) as soon, had rather, had better, had sooner, cannot but, may/might as well
[例1]You________ all those calculations! We have a computer to do that sort of thing.
A. needn’t have done B. must not have done
C. shouldn’t have done D. can’t have done
[例2]I ________to him because he phoned me shortly afterwards.
A. ought to have written B. must have written
C. couldn’t have written D. needn’t have written
[例3]You________ those letters. Why didn’t you
A. should post B. must have posted
C. should have posted D. ought to post