情态动词的正确使

1、情态动词的正确使用 1 must 的主要用法 must 可以表示义务和推测，当它表示推测时，其否定形式为cantcan not, 而must not, mustnt 表示“一定不要，不允许”。 The students smoke in the library. A cant B mustnt C maynt D dont have toB 2 need and dare 的主要用法 need 和dare 既可以与主语颠倒构成疑问句，在后面加not构成否定句，也可以像实意词一样用助动词构成疑问句和否定句。在疑问句和否定句中，dare 和need 常作情态动词。 Nobody tell the

2、old man that his son died in the war. A dares B dare C dare to D doesnt dare B 3 情态动词与动词的完成形式搭配 1）must have done 表示对过去事件的推测，用于肯定句中。否定句和疑问句中需用cant have done. You her in her office last Friday; shes been out of town for two weeks. A neednt have seen B must have seen C might have seen D cant have seenD

3、 2) shouldought to +have done表示过去应该发生而事实上没有发生的事情，意为“本应该”。它的否定形式为should not ought not to+ have done, 意为“本不该”，表示对过去不该发生而发生的事情的责备或惊讶。 The careless man received a ticket for speeding. He have driven so fast. A cant B wouldnt C shouldnt D mustntC 3) mightcould + have done 表示谈论过去的某种可能性，可能发生而没有发生，意为“本来可以本来

4、能够”。 Some women a good salary in a job instead of staying home, but they decided not to work for the sake of the family. A must take B should have made C would make D could have madeD 4) may have done 表示过去某种可能性，而这种可能性现在还存在，意为“或许已经”。 Research findings show we spend about two hours dreaming every nigh

5、t, no matter what we during the day. A should have done B would have done C may have done D must have doneC 5) neednt have done 表示做了不必做的事情，意为“其实不必，没有必要”，有时候可以用didnt have to do来表达。 It was very kind of you to do the washing-up, but you it. A mustnt have done B wouldnt have done C mightnt have done D didnt have to D 6) would+ have done 表示本来可以做的事情，通常用于虚拟语气。 The millions of calculations involved, had they been done by hand, all practical value by the