情態(tài)動詞 (3)

1、情態(tài)動詞should:可能性較大，但留有余地。“按道理/常理應(yīng)該”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”，有客觀依據(jù)，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 用于否定句和疑問句中， cant, 或could

2、nt 表示“不可能”，有客觀依據(jù)的否定的推測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，表示推測，可能性不大（might 可能性更?。﹎ay/mightHe may come or may not come. I am not sure about that. Tip: 表推測時，句中有not sure, 選may 或 might表猜測時，can/could 用于肯定句中，表示客觀可能

3、性，“有時會”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. 對現(xiàn)在/將來的推測： 情態(tài)動詞+ do 對過去的推測： 情態(tài)動詞+ have donecan&couldcan: 現(xiàn)在的能力could: 過去的能力 A blind person cant get across the road without help. My computer was

4、 broken, so I couldnt read your e-mails.will3. 臨時的決定-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失去某種功能The door wont open.need&dareneed/ dare 用作情態(tài)動詞常用于否定、疑問句 (dare有過去式dared)need/dare + v原型-Need I tell him ever

5、ything? -Yes, you must./ No, you neednt.need/dare 作實義動詞,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、態(tài)動詞的特殊考點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(表建議)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(與說話者的意愿相違背或表示不耐煩的情緒) Why must

7、 you interrupt me? If you must smoke, do it outside, please.should 竟然，居然（表示驚奇、憤怒、失望、遺憾等情緒） A well-educated man should be so rude to a lady! I dont know why you should think I did it.情態(tài)動詞+ have done1. 表推測2. 用于虛擬語氣中1、 must+have+done表示對過去事情的肯定推測，“一定做過某事”，該結(jié)構(gòu)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，因為地面還是濕的。推測2、 cant+have+done表示對過去事情的否定推測，“不可能做過某事”。 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，我剛才還在圖書館見過他。推測can+have+done表示對過去行為的懷疑，用于疑問句，“可能做過嗎？”。 There is no light in the room. Can they have gone out? 屋里沒有燈，他們可能出去了嗎？3、 may/mi

9、ght+have+done表示對發(fā)生過的事情的推測， “可能已經(jīng)”或“也許已經(jīng)”，用于肯定句中。 What has happened to George?I dont know. He may have got lost.喬治發(fā)生了什么事？我不知道，他可能迷路了。推測情態(tài)動詞用于虛擬語氣中 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 本應(yīng)該做但實際上沒做shouldnt+have+done 表示本來不應(yīng)該做某事，而實際做了。 2. He could have passed the exam, but he was too careless. could have done 過去本能夠做而實際上未做，帶有遺憾的語氣He might have given you more help, even though he was very busy.may/might have done 過去本來可能而實際上未發(fā)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，過去本來會做而實際上未發(fā)生Mark neednt have hurried. After driv