語法學案：情態(tài)動詞(Modal Verbs)課件

1、語法學案5：情態(tài)動詞（Modal Verbs）*概 說助動詞(auxiliary)主要有兩類：基本助動詞(primary auxiliary)和情態(tài)助動詞(modal auxiliary)。基本助動詞有三個：do, have和be；情態(tài)助動詞有十三個：may, might; can, could; will, would; shall, should; must, need, dare, used to, ought to. 上述兩類助動詞的共同特征是，在協助主動詞構成限定動詞詞組時，具有作用詞的功能：1）構成否定式：He didnt go and neither did she. The m

2、eeting might not start until 5 oclock.2）構成疑問式或附加疑問式：Must you leave right now? You have been learning French for 5 years, havent you?3）構成修辭倒裝：Nowhere can he obtain any information about his sister. Hardly had he arrived when she started complaining.4）代替限定動詞詞組：A: Who can solve this crossword puzzle? B

3、: Tom can.A: Shall I write to him? B: Yes, do.情態(tài)動詞的概念：情態(tài)動詞具有詞匯意義，但意義不夠完整，一般不能單獨作謂語。情態(tài)動詞表示說話人的語氣和態(tài)度。情態(tài)動詞的特征：1. 后面一般+動詞原形2. 一般沒有人稱和數的變化即第三人稱單數不加-s3. 一般只有現在式和過去式兩種形式，但可以表示現在時間，過去時間和將來時間。4. 情態(tài)動詞沒有非謂語形式，即沒有to do, doing, done等形式現代英語語法還將be able to(能夠), had better(最好), would rather(寧愿),used to(過去常常)等列為情態(tài)動詞。

4、I. 情態(tài)動詞基本用法：情態(tài)動詞用法否定式疑問式與簡答can能力（體力，智力，技能）允許或許可（口語中常用）可能性（表猜測，用于否定句或疑問句中）can not / cannot /cant doCan/Coulddo?Yes,can.No,cant.couldcouldnt domay可以（問句中表示請求）可能，或許（表推測）祝愿（用于倒裝句中）may not do Maydo? Yes,may.No,mustnt/cant.mightmight not doMightdo? Yes,mightNo,might not.must必須，應該（表主觀要求）一定，想必（肯定句中表推測）偏偏、硬要(

5、指做令人不快的事)must not/mustnt doMustdo? Yes,must.No,neednt/dont have to.have to只好，不得不（客觀的必須，有時態(tài)人稱變化）dont have to doDohave to do?Yes,do. No,dont.ought to應當（表示義務責任，口語中多用should）ought not to/oughtnt to doOughtto do?Yes,ought. No,oughtnt.shall將要，會,必將用于一三人稱征求對方意見用于二三人稱表示規(guī)定、許諾、命令、警告、威脅等shall not/shant doShalldo

6、?Yes,shall. No,shant.should應當，應該（表義務責任）可能，應該（表示推測）竟然（表示驚訝和難以置信,表示說話人的感情：驚奇、憤怒、失望等)本該（含有責備意味）should not/shouldnt doShoulddo?will意愿，決心請求，建議，用在問句中would比較委婉will表示現在的習慣 would表示過去的習慣will not/wont doWilldo?Yes,will. No,wont.wouldwould not/wouldnt dodare敢（常用于否定句和疑問句中）dare not/darent doDaredo?Yes,dare. No,da

7、rent.need需要必須（常用于否定句和疑問句中）need not/neednt doNeeddo?Yes,must. No,neednt.used to過去常常（現在已不再）used not to dousednt/ usent to dodidnt use to doUsedto do?Yes,used. No,use(d)nt.Diduse to do?Yes,did. No,didnt.II. 表示推測常用的情態(tài)動詞must, can, could, may, might（推測語氣遞減）不同的“肯定”程度可按下列層次排列： He is at home. (事實) He must be

8、 at home.（非?？隙ǖ耐茢啵?He could be at home.（很可能） He may be at home.（僅僅可能而已） He might be at home.（或許, 非常不確定） He might not be at home.（也許不在家） He may not be at home. （比might可能） He couldnt be at home.（很可能不在家） He cant be at home.（一定不在家）He isnt at home.（事實） 1. must“肯定，一定”語氣強，只用于肯定句中。must + do(be)是推測現在存在的一般狀態(tài)進

9、行；must + be doing 推測可能正在進行的事情；must +have done是推測可能已經發(fā)生過的事情。He must be a man from America. / He must be talking with his friend. / He must have already arrived there.2. can和could“可能”，could表示可疑的可能性，不及cant語氣強，用于肯定、否定、疑問句中。The weather in that city could be cold now.We could have walked there; it was so

10、near.（推測某事本來可能發(fā)生，但實際上沒有發(fā)生）Can he be in the office now? No, he cant be there, for I saw him in the library just now.(語氣很強，常用于疑問句和否定句中)3. may和might“也許”，后者語氣弱，更沒有把握?？捎糜诳隙ň浜头穸ň洹?） 表示可能性（possibility）,用于對現在，過去或將來的推測，暗示不確定。might 不是may的過去式，它所表示的可能性比may 小，含較多的懷疑。He may be very busy now. (可能性較大) He might be v

11、ery busy now. (可能性較小)2） 表示許可（permission），表示允許別人做某事， 也可征求對方的許可。He may go now. We may keep the book for two weeks.3） 用于祈使句，表示祝愿。May you succeed! May you have a nice trip!III. 情態(tài)動詞注意點：I. can (could)表示體力或腦力方面的能力，或根據客觀規(guī)律能做某事的能力，意思是“能夠”。can表“能夠”時，既可指將來，也可指現在。be able to在表示能力時與can同義，be able to可以表達“某事終于成功”，而

12、can無法表達此意。be able to可用于各種時態(tài)，強調通過努力克服困難成功地做成某事，相當于managed to do 或 succeeded in doing。My grandma is over eighty, but she can/ is able to read without glasses.We can/ will be able to talk about the matter later.can (could)表示許可、允許，在疑問句中表示“請求，許可”，否定句中表示“不許”，此時可與may通用，有時cannot可以表示“禁止”，相當于“mustnt”。can (cou

13、ld)表示推測，強調客觀可能性“可能、會”，can多用于疑問句和否定句，表示猜測時，情態(tài)動詞后可用進行式或完成式。could表示“能力”“可能性”“許可”，為can的過去式。一般用于委婉、客氣地提出問題或陳述看法，此時can，could并沒有時間上的差別，只是could的語氣更委婉些。回答時用can回答。Liz, can you do me a favor?Excuse me, could you tell me the way to the station?I wonder if you could help me. (request請求) - Could I use your phone?

14、 -Yes, of course. You can. Do you think I could borrow your bike. (permission許可)*需要注意的幾點:表示猜測，can一般不用于肯定句中，除非是“經驗之談” 。這時can可以表示客觀的可能性,并不牽涉具體的事情是否會發(fā)生;要表示某事發(fā)生的可能性別時需要用could，may， might。Children can often get ill suddenly（小孩常?？赡芡蝗簧。〤ertain things in the home can be dangerous，especially if you have youn

15、g children（家里的某些東西可能有危險，尤其是有小孩的時候。）上面兩句可以看作醫(yī)務工作者或撫養(yǎng)過孩子的人說的話，屬“經驗之談”。Accidents can happen on such rainy days. II. may (might)表示許可，有“可以”的意思，詢問一件事可不可以做，有時可以與can互換。其否定式may not表示“不可以、禁止、阻止”等，常用must not=mustnt代替，may用于疑問句中，回答這種問題時，多避免用may，而用其他形式，以免顯得口氣太嚴峻或不客氣。表推測、或許、可能的意思，表示一件事或許會發(fā)生，只用在陳述句中。表祝愿: May you su

16、cceed! = I hope you may succeed. May you be happy, healthy and wealthy!might是may的過去式，表示可以做的事或可能發(fā)生的事；主句謂語動詞是過去時態(tài)時用 might不用may。might一般用于比may的口氣委婉，或表示現實的可能性更小一些的語境中。III. must, have to表示必須要做的事，意為“必須“，否定式 mustnt表示“不應該，不許可，禁止”等。因此，在回答帶有must的問句時，不用mustnt，而用 neednt或dont have to.must在表示“必須”時與have to相近，have t

17、o比較強調客觀的需要，must著重主觀看法。另外must不像have to那樣能有更多的時態(tài)。表推測，暗含很大的可能性，意為“一定”，只用于“肯定句”中。偏偏、硬要、干嘛(指做令人不快的事)。如： Heyboys！ Must you shout so loudly?must與have to都可以表示“必須”的意思，但要注意以下兩點區(qū)別。1) must只有現在時，而have to有現在時、過去時和將來時。如：We must work hard, or well fail in the examinationYears ago, the poor girl had to leave school

18、for lack of money2) must表示主觀看法，have to則側重于客觀需要。如：We must be strict with ourselves in everythingIn cities with many cars, some people have to wear masksIV. shall Shall she go to the concert with us this evening (征求意見)You shall go to the front at once(命令)Dont worryYou shall get the answer this very af

19、ternoon（允諾）He shall be sorry one dayI tell you(警告)Nothing shall stop us from fighting against pollution(決心)用于二、三人稱陳述句中。表示說話人給對方的命令、許諾、警告、強制、威脅、決心等。在疑問句中，表示征詢聽話人是否愿意。You shall fail if you dont work harder. （警告）He shall have the book when I finish reading it.(允諾)He shall be punished.(威脅)用于一、三人稱的疑問句中，表

20、示說話人征求對方的意見和向對方請示。Shall we put off the sports meeting until next month?Shall Tom go there with me tomorrow? should表示勸告、建議常作“應當”講，與ought to有時可互換，ought to更注重一些責任義務。should表示預測可能性，并譯作“可能，(按道理)應該”；而ought協則表示非常可能。should用于委婉、謙遜地提出意見或建議，ought to可表示因責任、義務等該做的事。a. should 表示勸告、建議、命令。You should go to class righ

21、t away.b. should 表示期待，用于表達合理推斷（prediction，意為“應該” ），或明顯的結果（意為“可能”）且所期待的事幾乎是事實。It is three oclock, the football game should begin now. Mary took dancing lessons for years, she should be an excellent dancer.V. will, would 表示意愿、意志和決心，適用于各種人稱，可以用來表示各種傾向或習慣動作。有時還用來表示“難免”。其過去式是would，也可以是單獨的情態(tài)動詞.在表示委婉提出請求、建

22、議或看法時，語氣比will委婉，常用于第二人稱，肯定的回答時用will. used to表示過去常常做現在已經不再有的習慣 would只表示過去的習慣或喜好，不涉及現在。1）表示意愿，表示愿意做或主動提出做，如意志，愿望或決心等，例如：That bag looks heavy, Ill help you with it.( offering to do sth)- You know that book I lent you. Can I have it back if youve finished with it?- Of course. Ill give it to you this aft

23、ernoon.(agreement)Thanks for lending me the money, Ill pay you back on Friday. (promise)2） 表示習慣(habit, custom)This old man is strange. He will sit for hours without saying anything.We would sit around Grandpa after supper, listening to his stories.3）表示請求（request）， 用于第二人稱， would 比will 更委婉。 例如：Will yo

24、u come this way, please?Would you open the window?*在表示將來的時間、條件狀語從句中，從句不能用will（這時的will不是情態(tài)動詞，而是助動詞，幫助構成將來時）。如：If it will rain tomorrow, we shall not go to the mountain village(誤)If it rains tomorrow, we shall not go to the mountain village(正)當情態(tài)動詞will表示意愿或決心時，是可以用于條件狀語從句的。如：If you will listen to me,

25、Ill give you some advice on how to learn English如果你愿意聽我的話，我將給你提點學習英語的建議。If you will come this way，the manager will meet you請您往這邊走，經理現在要見你。VI. may well和may/ might as well后都接動詞原形，是一種常用結構。may well+動詞原形相當于 to be likely to，意為“(完全)能，很可能”。may/ might as well+動詞原形相當于had better或幻have no strong reason not to，意

26、為“最好，不妨”。cannottoo/enough表示“無論怎么也不過分”，“越越好”；cannot but do sth表示“不得不，只好”的含義。. need和dare作情態(tài)動詞和實義動詞的區(qū)別：兩者作情態(tài)動詞時常用于否定句和疑問句。其形式為：neednt/darent do；Need/daredo?做實義動詞時，就有人稱，時態(tài)和數的變化，dare常出現過去時dared。其形式為：need(needs/needed)/dare(dares/dared) to do, dont(doesnt/didnt) need/dare to do（其中dare后面的to 常可以省略）某人需要做某事(s

27、b.) need (to) do某事需要被做(sth.) need to be done=(sth.) need doing 需要need，want, require等詞后面接doing主動形式表示被動意義dare做情態(tài)動詞How dare you say such a thing?= How do you dare (to) say ? dare做實義動詞dare做情態(tài)動詞He darent speak English before such a crowd, dare he? =He didnt dare (to) speak English before such a crowd, di

28、d he? dare做實義動詞.常用的情態(tài)動詞+have done表示對過去情況的推測或虛擬must have done sth.一定做某事can/could have done sth.本來能夠做某事，而實際上未做cant/couldnt have done sth.不可能做過某事ought to/should have done sth.過去本應該做某事而實際上并沒有做neednt have done 過去本不必做的事情實際上卻做了1. must +have done 表示對過去發(fā)生的事情作出的肯定推測。They are playing basketball, they must have

29、 finished their homework.他們在玩籃球，他們一定已經完成了作業(yè)。The road is wet. It must have rained last night.路是濕的， 昨天晚上一定下雨了。2. can/could have done “本可以, 本可能已經”用于肯定句中, 表示對過去發(fā)生的事情做出的推測或虛擬。 You could have had a better mark.你本來可以考的更好。He cant have slept through all that noise.You could at least have sent five cards.你本來可

30、以至少寄去5張明信片的。（說明沒有寄那么多）3. might/may have done, 表示對過去發(fā)生的動作進行可能性推測或虛擬。He may have gone to the clinic.他可能去醫(yī)務室了。He might have read about the news in the newspaper.他可能已經從報紙上知道這個消息了。4. should/ought to have done 過去本該做而沒有做的事情, 表虛擬，常含責備，悔恨。 You should have written with a pen, not a pencil. Yes, I know I ought

31、 to have, but I had no pen to write with. I was really anxious about you. You shouldnt have left home without a word. Im not feeling well in the stomach, I shouldnt have eaten so much fried chicken just now. 5. neednt have done 過去本不必做的事情實際上卻做了。You neednt have told him that. *.must表猜測語氣的反意疑問句的構成（可以不必

32、掌握）must表示推測時，其后的反意問句有兩種情況：對現存狀態(tài)（現在的事實）進行推測時，反意疑問句中動詞用其一般現在形式。對過去發(fā)生的事情進行推測時，若有表過去的時間狀語，反意問句用動詞的過去式。He must be reading, isnt he? You must do it yourself, dont you?He must have gone over the article, hasnt he? It must have rained last night, didnt it?Practice:1. -Must I start at once?-No, you_.A. needn

33、tB. mustnt C. cantD. wont2. -Need I hand in my exercise book at once?-Yes, you_.A. must B. need C. can D. will3. “The interest _be divided into five parts, according to the agreement made by both sides.A. may B. should C. must D. shall4. The room is so dirty. _ we clean it? Of course. A. Will B. Sha

34、ll C. Would D. Do5. I told Sally how to get there, but perhaps I _for her.A. had to write it outB. must have written it outC. should have written it out D. ought to write it out1. 析：A。由語境可知該答句表示“不必”，而mustnt表示“不準、禁止”，不符合語境，顯然應使用neednt表示“不必”，但肯定句回答繼續(xù)用must。2. 析：選A。根據規(guī)定need用于一般疑問句作肯定回答應換成must,而作否定回答時，使用

35、need的否定式neednt。3. 析：選D。4. 析：選B。上述兩題均考查 shall的常用含義，當shall 用于一、三人稱疑問句中時，表示征求對方意見；用于二、三人稱陳述句中，表示說話人給對方的命令、警告、允諾或威脅等。 5. 析：選C。分析語境可知，口頭上告知Sally如何去那里是不夠的，所以我本應書面告知，卻有沒書面告知之，顯得應使用should /ought to have written表示遺憾之情。選擇合適的詞或詞組填空1. I have a headache. I _ take an aspirin.(had better; would better)2. He looks

36、sleepy. He must _ bed very late last night. (go; have gone)3. I want to go to the office, but you _ with me. (need not to go; need not go)4. I ought _ those books to the library last week. (to have taken; to take)5. The mother is telling her son, “You _ eat with your fingers!” (wouldnt; mustnt)6. He

37、 was a good swimmer so he _ swim to the river bank when the boat sank. (was able to; could)7. To travel from England to Scotland you _ a passport.(dont need; neednt)8. He went on foot, but he _ by bus. (ought have gone; should have gone)9. A: Did Ken take the job in the bookstore? B: No, but I think

38、 he _. (must have; should have)10. He _ talk for hours, if you let him. (can; will)11. You _ use this toothbrush, its mine. (may not; shall not)12. No matter what people say, I _ do as I like. (shall; will)13. “Im willing to let you take whatever you like.” Means “you _ take whatever you like.” (sha

39、ll; will)14. A: I havent felt well for a week. B: You _ see a doctor. (had better; should have to)15. A: He is late, _ he have missed the bus? B: Yes, he must have missed the bus. (Can; Must)Keys:1. had better 2. have gone 3. need not go 4. to have taken 5. mustnt 6. was able to 7. dont need 8. shou

40、ld have gone 9. should have 10. will 11. shall not 12. will 13. shall 14. had better 15. Can選擇填空1. I didnt see her in the meeting room this morning. She _ at the meeting. A. mustnt have spoken B. shouldnt have spokenC. neednt have spoken D. couldnt have spoken2. One ought _ for what one hasnt done.

41、A. not to be punished B. to not be punishedC. to not punished D. not be punished3. If you really want yourself to be in good health, you must _ always _ so much. A. not; be smoking B. not; have smoked C. not; to smoke D. be not; smoking4. With so much work on hand, you _ to see the game last night.

42、A. mustnt go B. shouldnt go C. couldnt have gone D. shouldnt have gone5. Most of the students felt rather disappointed at the English party. They say that it _ better organized. A. had been B. had to be C. must have been D. could have been6. Im surprised that he _ in the exam. A. should fail B. woul

43、d have failed C. may have failed D. should have failed7. The little girl _ there alone. A. not dare go B. dares not go C. dare not go D. dare not to go8. “Must we do it now?” “No, you _.” A. wont B. neednt C. cant D. dont9. He said he would rather not _ it right now. A. doing B. to do C. do D. to be

44、 doing10. You _ to the meeting this afternoon if you have something important to do. A. neednt to come B. dont need come C. dont need coming D. neednt come11. Put on more clothes. You _ be feeling cold with only a shirt on. A. can B. could C. would D. must12. I _ play football than baseball. A. woul

45、d rather B. had better C. like better D. prefer13. I thought you _ like something to read, so I have brought you some books. A. may B. might C. could D. must14. There was plenty of times. She _. A. mustnt have hurried B. couldnt have hurried C. must not hurry D. neednt have hurried15. The plant is d

46、ead. I _ it more water. A. will give B. would have given C. must give D. should have given16. You _ return the book now. You can keep it till next week if you like. A. cant B. mustnt C. neednt D. may not17. Its still early, you _. A. mustnt hurry B. wouldnt hurry C. may not hurry D. dont have to hur

47、ry18. Please open the window, _? A. cant you B. arent you C. do you D. will you19. We _ for her because she never came. A. mustnt have waited B. shouldnt have waited C. mustnt wait D. neednt wait20. May I stop here? No, you _. A. mustnt B. might not C. neednt D. wont21. Its a fine day. Lets go fishi

48、ng, _. A. wont we B. will we C. dont we D. shall we22. I didnt see her in the meeting room this morning. She _ at the meeting. A. mustnt have spoken B. shouldnt have spoken C. neednt have spoken D. couldnt have spoken23. Please dont make a noise. _. Ill be as quiet as a mouse. A. Yes, I wont B. No,

49、I wont C. No, I will D. Yes, I will24. The young man has made so much noise that he _ not have been allowed to attend the concert. A. could B. must C. would D. should25. Where is John? He _ in the library. A. should be B. must be C. can be D. must have been26. Since the road is wet this morning, _ l

50、ast night. A. it must rain B. it must be raining C. it must have rained D. it must have been rain27. Will your brother stay home tonight? Im not quite sure. He _ to the cinema tonight. A. must go B. can go C. may go D. may be going28. Shes already two hours late. What _ to her? A. can have happened

51、B. may have happened C. should have happened D. must happen29. You must be a writer, _? A. mustnt you B. are you C. must you D. arent you30. I got up early that morning, but I _ so because I had no work to do. A. mustnt have done B. didnt need to do C. neednt have done D. cant have done31. He _ have come here yesterday, but he didnt. A. could B. should C. ought to D. all the above32. I missed the last bus, so I _ go home on foot. A. must B. have to C. may D. had to33. He ought to win the first prize, _ he? A. oughtnt B. shouldnt C. mustn