备考英语六级:情态动词

2017-03-21 00:00:00云梦 英语六级

  情态动词(Modal verbs)指本身有一定的词义,表示语气的单词。不能独立作谓语,只能和动词原形一起构成谓语。下面是一些关于情态动词的语法知识,希望能帮到大家!

  1.情态动词的完成式

  1)should/ought to have done——表示过去应该做的

  却没有做,常含有后悔、责备、埋怨的口吻,意为“本应该”,“应该就好了”; e.g. With all the work finished, I should have gone to your birthday party last night.

  2)shouldn’t/ought not to have done——表示过去不该

  做的事却给做了,也常含有责备、不满之意,意为“本不该”。

  e.g. You shouldn’t have gone back to work yesterday without the doctor’s permission.

  3)must have done——表示对过去的事情较有把握

  的、肯定性的推测,常译为“一定,准是,肯定”,其否定形式是can’t/couldn’thave done,意为“决不可能,不太可能”。

  e.g. Since the ditch is full of water, it must have rained last night.

 

  4)may/might have done——表示对过去的事情的推

  测,但不十分有把握,意为“可能,或许已经”。 e.g. A traffic accident happened yesterday and a driver may have been hurt.

  5)could have done——表示过去有可能或有能力做某

  事,而实际未做、未能实现的事;有时也表示轻度批评,意为“本来可以,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——表示过去做了某事,但没有做的必要,意为“其实没有必要”。 e.g. I needn’t have bought all that wine——only three people came.

  2、可作情态动词用的短语

  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

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