情态动词复习.ppt

3. could have done 它表示“过去本来能够…” 实际上没能做…。 If you could have finished the task in time，you could have been promoted. 如果你当时能如期完成那任务的话，你可能已提升了（实际上没有被提升） I could have laughed to hear him talk like that.听他那样讲话，我差点笑出声来。 4.might have done虚拟式表示与过去事实相反的假没结果。 If she had started a little earlier， she might have been in time for the train.如果她早点出发，她有可能及时赶上火车。(实际上没有早出发，便没有赶上火车) It might have been better to stop then.如果那时就停止的话，也许比较好。 5．would have done 它表示的是与过去事实相反之假设的结果，意思是“当时就会…了”而实际上没有… 　 I would have helped you if I had known of your difficulties . If it hadn‘t rained yesterday, we would have gone climbing .假如昨天没下雨，我们就去了。（实际上没有去）。 Practice With so much work on hand, you ____to see the game last night. A. mustn’t go B. could have gone C. shouldn’t go D. shouldn’t have gone 2. There was plenty of time. She ____. A. mustn’t have hurried B. couldn’t have hurried C. must not hurry D. needn’t have hurried Practice 3. –I saw Mary in the library yesterday. --You_____ her. She is still abroad.A. mustn’t see B. can’t have seen C. mustn’t have seen D. couldn’t see 4. Aunt Mary______the train, otherwise she would have arrived here by now.A. must have missed B. should have missedC. had missed D. might miss 四. 可兼做行为动词的情态动词：need 、 dare 情态动词 (+动词原形) 行为动词 need dare 1.无人称和数的变化; 2.尤其用于： *否定句及疑问句中; *在if/whether之后; *或与hardly, never, no one, nobody连用; 3.常以needn’t 和daren’t 的形式出现; 4.dare有其过去时dared. 多用于肯定句; (sb.) need to do dare to do (sth.) need to be done (sth.) need doing 五．其他情态动词用法 　１情态动词dare, need 通常用于否定句或疑问句 　 　Who dare do it? Dare you go out alone ? 　　dare, need 还可用作行为动词，可以用于各种句式，后面可跟加to的不定式 A. who dare do it? B. He dares to do it. A. He needn’t do it B. he needs to do it 上述句子中A句为含情态动词的句子，B句中dare. need 均为行为动词 He daren’t speak English before such a crowd, dare he? 判断正误: He daren’t to speak English before