情态动词 (3)

1、情态动词should:可能性较大，但留有余地。“按道理/常理应该”should：With her talent and experience, she should do well by herself.Its 4:30. They should be in New York by now.must: 最有把握，“一定”，有客观依据，只用于肯定句must:He is wearing a long face. He must be angry.Something must be burning. I can smell it.can, could 用于否定句和疑问句中， cant, 或could

2、nt 表示“不可能”，有客观依据的否定的推测can/couldThere is someone outside. Who can it be?cant/ couldnt That cant be Mary since she is hospital now.may, might, 主要用于肯定句中，表示推测，可能性不大（might 可能性更小）may/mightHe may come or may not come. I am not sure about that. Tip: 表推测时，句中有not sure, 选may 或 might表猜测时，can/could 用于肯定句中，表示客观可能

3、性，“有时会”Anyone can make mistakes.can/couldIt is usually cold here in winter but it can be rather warm.He is very rude, but he can be very friendly at times. 对现在/将来的推测： 情态动词+ do 对过去的推测： 情态动词+ have donecan&couldcan: 现在的能力could: 过去的能力 A blind person cant get across the road without help. My computer was

4、 broken, so I couldnt read your e-mails.will3. 临时的决定-Tom was sent to hospital yesterday. - Im sorry to hear that. Ill go and see him.If you will wait, Ill get it for you.4. sth wont do sth失去某种功能The door wont open.need&dareneed/ dare 用作情态动词常用于否定、疑问句 (dare有过去式dared)need/dare + v原型-Need I tell him ever

5、ything? -Yes, you must./ No, you neednt.need/dare 作实义动词,多用于肯定句need/dare to do sth sth need doing = sth need to be doneShe doesnt dare to tell the boss the secret.You neednt tell me what you know, because Im not asking you. You didnt need to stay until midnight.I wonder how he dared say that to you.情

6、态动词的特殊考点may 用于祈使句句首表示祝愿 May our country long live! May you stay young!may/might as well do sth 不妨做(表建议)may/might well do sth 可能做may/might well not do sth 完全不可能做.You may/might as well try this hat.They may/might well win.They may/might well not come here today.must 偏要，非要(与说话者的意愿相违背或表示不耐烦的情绪) Why must

7、 you interrupt me? If you must smoke, do it outside, please.should 竟然，居然（表示惊奇、愤怒、失望、遗憾等情绪） A well-educated man should be so rude to a lady! I dont know why you should think I did it.情态动词+ have done1. 表推测2. 用于虚拟语气中1、 must+have+done表示对过去事情的肯定推测，“一定做过某事”，该结构只用于肯定句。 It must have rained last night, for t

8、he ground is wet. 昨晚一定下雨了，因为地面还是湿的。推测2、 cant+have+done表示对过去事情的否定推测，“不可能做过某事”。 Mr. Smith cant have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了，我刚才还在图书馆见过他。推测can+have+done表示对过去行为的怀疑，用于疑问句，“可能做过吗？”。 There is no light in the room. Can they have gone out? 屋里没有灯，他们可能出去了吗？3、 may/mi

9、ght+have+done表示对发生过的事情的推测， “可能已经”或“也许已经”，用于肯定句中。 What has happened to George?I dont know. He may have got lost.乔治发生了什么事？我不知道，他可能迷路了。推测情态动词用于虚拟语气中 1. I should have watched the movieit turned out to be fantastic. Look, Tom is crying. I shouldnt have been so harsh on him.should have done/ ought to have

10、 done 本应该做但实际上没做shouldnt+have+done 表示本来不应该做某事，而实际做了。 2. He could have passed the exam, but he was too careless. could have done 过去本能够做而实际上未做，带有遗憾的语气He might have given you more help, even though he was very busy.may/might have done 过去本来可能而实际上未发生I would have told you all about the boys story, but you didnt ask me. Without your help, I wouldnt have achieved so much.would have done，过去本来会做而实际上未发生Mark neednt have hurried. After driv