情態(tài)動詞(Modal Verbs).ppt

1、情態(tài)動詞（Modal Verbs),can, could, may, might, will, would, shall, should, must和ought稱為情態(tài)動詞。它們和 主要謂語動詞一起構(gòu)成謂語。絕大多數(shù)情態(tài) 動詞的意思可以劃分為兩類。 一類是表示可能性：情態(tài)動詞可以用來表示某種情況是肯定的、或很可能的、或可能的、或不可能的。,另一類意思涉及必須做某事或允許做某 事之類的意思：情態(tài)動詞可以用來表示 某人必須做某事、某人能做某事，如果 某事發(fā)生（或不發(fā)生）就會好一些，或 者某事是許可或禁止的。,一、表示有把握的程度情態(tài)動詞可以表達(dá)對于某一事實或事件有把握的各種不同程度。,a完全有把握

2、(肯定的或否定的）,shall用于第一人稱： I/We shall be away tomorrow. I shant be late on Wednesday. 2. will 用于各種人稱： Thats the phone. Thatll be Tony. Things will be right. It wont rain this evening. Youll be right.,3. must只用于肯定句中： He decided Franklin must be suffering from a bad cold. 4. cant和couldnt表示現(xiàn)在或?qū)聿豢赡埽?couldn

3、t用于間接引語中，表示過去不可能： That cant be Mr. Smithhes in New York. I knew it couldnt be Mr. Smith. He couldnt be at home. 5. would, wouldnt 用于間接引語中，表示過 去可能或不可能： I told you wouldnt be ready in time.,1. should, shouldnt, ought to, oughtnt to, may well (很有可能）, may, may not （可能、可能不） : She should/ought to be here

4、soon. It shouldnt/oughtnt to be difficult for you to work out the problem. 3. We may be buying a new flat. 4. The list may not be complete. 5. “I think its going to rain.” “You may well be rightthe sky is really black.,b很有可能/可能,C可能性小,might, mightnt, could,它們不是may, can的過 去式，它們都可以用來談?wù)摤F(xiàn)在和將來, could比may

5、和might更不可能： I might see you againwho knows? Things might not be as bad as they seem. We could all be millionaires one day.,d在理論上可能或現(xiàn)實可能性,can可以用于肯定句中表示理論上的可能性，或與be動詞連用，表示有時： 1. Poor posture (姿勢）can cause neck ache, headaches and breathing problems. 2. New England can be very warm in September. 3. Can

6、 gases freeze?,2.表示某事將會實際發(fā)生，或真實情況的現(xiàn)實可能性通常用may, might或could: 1)-I think Labour are going to win. -You may be right. 2)-Where is Emma? -I dont know. She may be out shopping. 3) Peter might call. If he does, ask him to ring later. 4) She didnt say hello. She may not have recognized you. 5) -Wheres Sara

7、h? -She may/ might/ could be at Joes place.,e在條件句中表示有把握或可能,would, wouldnt, could, couldnt, might, mightnt可以用在含有條件句的主句中表示可能： If we had enough time, things would be easy. I wouldnt do this if I didnt have to. If John came we could all go home. I couldnt do anything without your help. It mightnt be a b

8、ad thing if we took a short holiday.,詢問可能性,might表示可能性,可以和could/can一樣用在問句中，詢問可能性。也可用于肯定、否定句中。 Might it be possible to make computers the size of a pinhead one day? Might/ Could/ Can he still be working? Might/ Could/ Can he have been waiting long? 4. Might/ Could he have left by tomorrow?,“could, mig

9、ht, ought to, should, would和neednt +have +過分的用法,1.could, might, ought to, should, would和 neednt + have +過分,常用來表示非真實的情況: Did you see him fall? He could have killed himself. 2. You should have called-I was getting worried. 3. I would have gone abroad if I had had more money. 4. She neednt have sent he

10、r mum flowers.,情態(tài)動詞 modal verbs,的 特點(diǎn) 1）有特定的詞義 2）沒有人稱和數(shù)的變化 3）其后加動詞原形(do), have done ,be doing.,情態(tài)動詞,情態(tài)動詞,1。區(qū)別must / have to Must表示人在主觀上認(rèn)為的必要、必須、一定要 Have to表示受環(huán)境或習(xí)慣支配的客觀必要 “不得不”，能用于更多時態(tài)。 1)Soldiers _obey officers. 2)Its raining outside.We_stay at home. 3As he had broken his leg， he _lie in bed.,易混易錯用的

11、情態(tài)動詞,must,have to,had to,2。表示能力: can, could, be able to *be able to 能用于各種時態(tài)。 can / could 只能表示現(xiàn)在或過去的能力。 *was / were able to : “設(shè)法做成某事” 相當(dāng)于 managed to do sth. succeeded in doing sth.。 Eg.Though they were trapped in the big fire, they _escape.,were able to,4。注意對need問句的回答: -Need I finish the work today?

12、 -Yes, _. No, _. No, _.,you must,you neednt,you dont have to,-Shall I tell John about it? -No, you _. -Must we do it now? -No, you _.,neednt (dont have to),neednt (dont have to),6.表示推測情態(tài)動詞的重要用法.,肯定的推測 可能的推測 否定的推測 疑問的推測,must,對將來 對現(xiàn)在 對過去,情態(tài)動詞,may, might,cant, couldnt,can, could,+ V. + V. + have done 常

13、見must be + be doing,+ V. + V. + have done + be doing 可以用not表示“可能不”,+V. + V. + have done + be doing,+ V. + V. + have done + be doing,2. can (用于疑問句中）， cant, could, may, might, should, ought to, will, must + have + 過分可以表示對過去發(fā)生的事情作出推斷： Where can he have gone? We cant have taken it upstairs this morning!

14、 I may / might/ could have come to a wrong conclusion. 4. That was a bad place to go skiing. You might have broken your leg.,5. -A woman phoned while you were out. -It must have been Kate. John should/ ought to have arrived yesterday. 7. I wonder why we havent heard from him- do you think he wont ha

15、ve got our letter yet? 8. We cant go and see them now- theyll have gone to bed.,3.can (用于疑問句中）， cant/ could/ may/ might/ should/ ought to/ will/ must + have + 過分也可以表示某事可能已經(jīng)發(fā)生，該用法類似現(xiàn)在完成時和將來完成時： 1. Ill try phoning him, but he might have gone out by now. 2. By the end of this year I might have saved so

16、me money. 3. John should /ought to have left by tomorrow. 4. Thatll have been Roland. He said hed be back at 7 oclock.,二、表示必須和允許做某事,情態(tài)動詞可表示必須和允許做某事的各種含義。情態(tài)動詞的這類用法很重要，可以有禮貌地表達(dá)請求、建議、邀請和批示。 a must, will, need (用于疑問句中）強(qiáng)調(diào)必要性；shall(用于二、三人稱表示說話人的意愿、承諾、命令或法律、規(guī)章、制度上要求必須做的事情） ：,Teachers of English must be in

17、the classroom by 7.10. All sales staff will arrive for work by 9.00. Need I get a visa for Hong Kong? You shall have the book as soon as I finish it. He shant come here. He shant pass the math exam. A record shall be kept of the number of students attending each class.,8. “Can someone help me?” “I w

18、ill.” 9. Ill definitely pay you back next week. 10. Ill kill her for this, Sue said. 11. “Give me a kiss.” “No, I wont.” 12. The car wont start. would指過去愿意；wouldnt指過去拒絕： My husband would do the dishes, but he wouldnt cook. I asked him politely, but he wouldnt tell me. The car wouldnt start this morn

19、ing.,must, have to 和have got to,這三種形式一般可以互換，用于第一人稱時，可以表示 “客觀上必須”，在下列情況下，have to/have got to也許比must更合適： We have to/ have got to send these VAT forms back before the end of the month.(即法律要求我們這樣做） 另一方面，must可表示說話人認(rèn)為自己有權(quán)做某事，下列句中用must可能比have to/have got to更合適： I/ We really must do something about the weed

20、s in the garden.(別人不會要求我們）,must （不用have to/ have got to) 用于公告或文件中： Cyclists must dismount. Candidates must choose five questions. 在表示“非得，偏要”時，一般用must: Must you always interrupt me when Im speaking? must也可以表示懇切的邀請： You really must come and see us some time. must還可以用于強(qiáng)調(diào)勸告： You really must take a holid

21、ay this year.,b 我們可以用will you告訴人們做什么; would you語氣更婉轉(zhuǎn)、更客氣。Will you?可以表達(dá)人們的愿望；Wont you?表示懇切地勸人接受; could, would表示請求別人為我們做事 ：,Will you send me the bill, please? Come this way, will you? Will you be quiet! Would you open the window, please? Would you mind standing up for a moment? Come this way, would yo

22、u? Will you have some more dessert? What will you drink? Wont you have some more toast?,You mustnt drive fast. Theres a speed limit. Magazines may not be taken out of the library. You cant come in here without permission.,c 禁止 mustnt, may not, cant 可以表示禁止，may not非常正式，在非正式文體中cant更常見；mustnt比may not 更為

23、強(qiáng)調(diào)：,If you will come this way I should be grateful if you would let me know your decision as soon as possible. Ill pay for the drinks. Anyway, youre here. You might as well stay. Shall I give you a hand?,e 許可:can, may, could/might (用于征求許可)，給予許可時要用may, can:,1. -Can I borrow your laptop? 2. -Could I a

24、sk you something if you are not too busy? -Yes, of course you can. (不能用You could) 3. -Might I come in? -Of course, you may. (不能用might) 4. May I use your mobile phone? 5. Do you think I might take a break?,f 沒有必要:neednt do, neednt have done(表示過去沒有必要做而實際做了的事情；didnt need/didnt have to do表示過去沒有必要做而實際也未做

25、的事）,You neednt work this Saturday. You neednt have watered the flowers, for its going to rain. I didnt have to cut the grass myself. My brother did it.,g 表示能力：can, could只有現(xiàn)在時和過去時, be able to do有更多的時態(tài)。表示過去的能力和在否定句中表能力時，用could和was/were able to do均可： Jim could/couldnt /was/wasnt able to run very fast w

26、hen he was a boy. He said he could see me next week. 表示成功地完成某一具體動作時，通常不用could，而用was/were able to/ managed to/succeeded in + doing： In the end they were able/managed to rescue/succeeded in rescuing the cat on the roof.,其他意思： 1. must 可以表示偏要：If you must drink so much, of course youll feel sick.Naturall

27、y, after I gave her my advice, she must do the opposite.2. will可以表示常常，would可以表示過去習(xí)慣性的行為。used to用來談?wù)摿?xí)慣性行為或習(xí)慣性狀態(tài)，而would只可談?wù)摿?xí)慣性行為:,Most evenings hell just sit in front of the TV and go to sleep. When we were kids, my mum would take us out on bikes all around the countryside. She will fall in love with the wrong people. If something breaks down, and you kick