情態(tài)動詞情態(tài)動詞有：can (could), may (might), shall (should), will (would), must, have to, need, dare (dared), ought to, used to. 情態(tài)動詞無人稱和數(shù)的變化，不能獨立使用，它與其后面的動詞原形合成謂語。情態(tài)動詞的具體用法如下：1 can1）表示能力 能，能夠A computer can not think for itself, it must be told what to do.2）表示可能（理論上或是邏輯判斷上）。The temperature can fall to 60, that is 60 below freezing. 氣溫可降至60，也就是零下60。He cant (couldnt) have enough money for a new car. 他不可能有足夠的錢買新車。3）表示驚異、懷疑、不相信的態(tài)度。（主要用在否定句、疑問句或驚嘆句中）“是否有可能”_ it be true that your bike was stolen again? (Is it possible?)How _ you be so careless!_ anyone be such a fool as to believe that?4）用來表示一種可能出現(xiàn)的事情，或表示某事、某物、某人偶然或通常有做出什么事的傾向。通常（但并非總是）指不愉快的事情?；虮硎灸承┨厥馇闆r下的可能性,客觀的可能性O(shè)ur house is on the top of a hill, and in winter the winds _ be pretty cold. The World Wide Web is jokingly called the World Wide Wait, for sometimes it can be very slow.It can be very cold in the mountains.Accidents can happen on such rainy days.I would rather go shopping alone than go with her because she can be rather tiresome at times.比較：Driving on these roads _ be a very nerve-racking business.Driving on this icy road _ be dangerous today.5）比較委婉客氣地提出問題或陳述看法。Can (Could) you lend me a hand? 幫我一把好嗎？Im afraid we couldnt give you an answer today. 恐怕我們今天不能給你答復(fù)。6) can表示能力時，還可用be able to代替。如：I could / was able to play chess when I was six.但be able to 可用于各種時態(tài)Ill not be able to come this afternoon.I have been able to do the work.I hope to be able to do the work.區(qū)別：Something was wrong with my car, but I _ drive it to the garage.= Something was wrong with my car, but I _ drive it to the garage.= Something was wrong with my car, but I _ drive it to the garage.be able to 可以表示經(jīng)過努力或克服了困難之后做成了某事，相當(dāng)于manage to do , succeed in doing 7)表推測 cant have done 表示對過去發(fā)生的事情的否定推測She cant be at home now, for the lights are all out.It cant have rained last night, for the ground is dry.8) can 的習(xí)慣用法It is as good as can be.不能再好了。One cannot be too careful to drive a car./ in driving a car.One can not but be moved by his noble deeds.人們不能不為他那高尚的行為所感動。cant/couldnt help doingcant/couldnt help to do2. could1) can 的過去式I could speak a little Japanese when I was at college but now I have forgotten all of them except a few words.2) 客氣的請求Could I borrow your dictionary?Yes/Of course, you can.3) could用在肯定句中表示一種比較婉轉(zhuǎn)的懷疑。His story _ be true, but I hardly think it is.4) could have done表示對過去能做而未做的事感到惋惜、遺憾。意思是“本可以；可能已經(jīng)做了某事”I stayed at a hotel while in New York._ Oh, did you? You could have stayed with Barbara.5) couldnt have done”表示對過去情況的推測，意思是“不可能做了”。例如：He could not have seen the film because he knew nothing about it.3.may,might1）表示許可，might可以指過去時間，也可指現(xiàn)在時間，語氣更委婉。You may take whatever you like. 你喜歡什么就拿什么。May (Might) I ask for a photo of your baby? 我可以要一張你寶寶的照片嗎？May I use your car? No, you mustnt.(Sorry, but Im using it now./Youd better not.)在回答以may引起的問句時，多避免用這個詞，而用其它方式，如Yes, please. / Certainly. / Please dont ./ Youd better not. / No, you mustnt.等，以免顯得太嚴(yán)峻或不客氣。2）表示可能（可能性較 must 和 can 小）。might可以指過去時間，也可以指現(xiàn)在時間，但語氣更加不肯定。Peter may come with us tonight , but he isnt very sure yet.They might be having a meeting, but Im not sure. 他們有可能在開會，不過我不肯定。3) may/might have done表示對過去的推測。Its too late. He may have gone to bed.Yesterday ,Jane walked away from the discussion. Otherwise ,she might have said something she would regret later.4. shall1）表征詢意見，用于第一、第三人稱疑問句。Shall I get you some tea? 我給你點茶好嗎？2）表說話人的意愿，有“命令、允諾、警告、威脅”等意思，用于第二、第三人稱陳述句。You shall do as I say. 按我說的做。（命令）You shall have my answer tomorrow. 你明天可以得到我的答復(fù)。（允諾）You shall fail if you dont work hard. (警告)3)當(dāng)宣布法律、規(guī)定時It has been announced that candidates shall remain in their seats until all the papers have been collected.(規(guī)則或規(guī)定)5. should1）表義務(wù)。意為“應(yīng)該”（某件事宜于做），用于各種人稱。You should be polite to your teachers. 你對老師應(yīng)該有禮貌。You shouldnt waste any time. 你不應(yīng)該浪費時間。2）表推測，意為“想必一定、照說應(yīng)該、估計”等。The film should be very good as it is starring first-class actors. 這部新電影是一流演員主演的，估計拍得很好。They should be home by now. 照說他們現(xiàn)在應(yīng)當(dāng)已經(jīng)到家了。- When can I come for the photos? I need them tomorrow afternoon.- They should be ready by 12:00.3). 在名詞性從句中表感情，即說話人認(rèn)為應(yīng)該如此。例如：It is natural that students should study hard.4). 表示“竟然”Swine flue should have nothing to do with pigs.5). should have done 表示過去應(yīng)該做而未做某事。含有惋惜、責(zé)備的意味。例如：We should have studied last night, but we went to the concert instead.6. will1）表意愿，用于各種人稱陳述句。None is so blind as those who wont see. 不愿看的人眼最瞎。If you will read the book, Ill lend it to you. 如果你愿意讀這本書，我會把它借給你。2）表示詢問對方的意愿或向?qū)Ψ教岢稣埱?，用于第二人稱的疑問句中Will you close the window? Its a bit cold. 請你把窗戶關(guān)上好嗎？有點冷。Wont you drink some more coffee? 再來一點咖啡好嗎？3）表示某種傾向或習(xí)慣性動作。Fish will die out of water. 魚離開水就不能活。The boy will sit there hour after hour looking at the traffic go by. 那男孩常常坐在那里好幾個鐘點，看著車輛行人通過。4) 表功能The door/window wont open.7.would1）表意愿。They would not let him in because he was poorly dressed. 他們不讓他進(jìn)去因為他衣著破舊。2）表委婉地提出請求、建議或看法，比 will 客氣。Would you like another glass of beer? 再來杯啤酒好嗎？They wouldnt have anything against it. 他們不會有什么反對意見。3）表過去反復(fù)發(fā)生的動作或過去的一種傾向。Every time she was in trouble, she would go to him for help. 她每遇到麻煩都會向她求助。他告訴我盒子打不開了。Whenever I passed his house I would see him standing under the big tree.8. must1）表示義務(wù)或強烈的勸告，意為“必須”，否定式表示“禁止”、“不準(zhǔn)”。在回答 must 的問句時， 否定回答用 neednt 或 dont have to .。We must do everything step by step. 我們一切都必須循序漸進(jìn)地做。-Must we hand in our exercisebooks now? 我們現(xiàn)在就要交練習(xí)本嗎？-No, you neednt. / No, you dont have to. 不必。2）表示對現(xiàn)在情況的推測用“must + 動詞原形”。意為“想必、準(zhǔn)是、一定”等，只用于肯定句。He must be ill. He looks so pale. 他準(zhǔn)是病了。他的臉色蒼白。Shes wearing a diamond necklace. She must have a lot of money.她戴著鉆石項鏈，一定很有錢。3）對過去情況的猜測用“must+ have +過去分詞”。例如：It must have rained last night, for the ground is wet.4) 表示“偏要、硬要”做某事How old are you, Madam?If you must know, Im twice my sons age.9. ought to 1）表義務(wù)，意為“應(yīng)該”（因責(zé)任、義務(wù)等該做），口氣比should稍重。You are his father. You ought to take care of him. 你是他父親，應(yīng)當(dāng)管他。You oughtnt to smoke so much. 你不應(yīng)該抽這么多煙。2）表推測，暗含很大的可能，語氣較弱。Han Mei ought to know his telephone number. 韓梅該知道他的電話號碼。Theres a fine sunset; it ought to be a fine day tomorrow. 今天有晚霞，明天應(yīng)該是個好天。3) ought to have done 表示過去應(yīng)該做而未做的事情。例如：You ought to have helped him. (but you didnt)1、can ,和be able to can 和be able to 在表示“能力”時意思相同，但在用法上有區(qū)別。1). can 表示主觀能力， be able to 表示客觀能力。can 表示有這種能力或機會，be able to 則表示經(jīng)歷一番艱難后能夠做成某事。例如：I can drive , but Im not able to drive now because Im drunk.The fire spread through the hotel very quickly but everyone was able to get out.2). can只有兩種時態(tài)形式，現(xiàn)在式can和過去式could，而be able to有多種時態(tài)形式。Mary can play the piano. She has been able to play it since she was 5. 3). be able to 可用于動詞不定式和動名詞結(jié)構(gòu)中， can 不能。例如：I regret not being able to take his advice.2. must和 have tomust表示主觀意志，而have to表示由于客觀因素不得不做某事。I told her that she must give up smoking. 我叫她必須戒煙。We had to get everything ready that night. 我們那晚得把一切準(zhǔn)備就緒。Its getting dark. I have to be off now.3. need和dare need和dare既可用作情態(tài)動詞，也可用作實義動詞。用作情態(tài)動詞時，主要用于否定句和疑問句。用作實義動詞時，可用于各種句式。1) 用作情態(tài)動詞 need do / neednt do dare do / dare not do dare有過去式dared You neednt telephone him now. 你現(xiàn)在不必打電話給他。I dont think you need worry. 我想你不必發(fā)愁。She dare not go out alone at night. 她晚上不敢一個人出去。How dare you say Im unfair? 你竟敢說我不公平？I wonder how he dared say that to the teacher.2) 用作實義動詞 need to do / dont(doesnt/didnt) need to do dare to do/ dont(doesnt/didnt) dare (to) do You dont need to do it yourself. 你不必親自做這件事。We need to tell them the news. 我們需要把這消息告訴他們。We should dare to give our own opinion. 我們要敢于提出自己的觀點。He did not dare (to) look up. 他不敢抬頭看。3) need 構(gòu)成一般疑問句時，其肯定回答用must ，否定回答用 neednt 。Need I do it now?Yes, you must. (No, you neednt.)4) need (not) have done表示“本有 （無）必要做某事，然而做了（沒有做）”。You neednt have told him about the news. He had known it long before.4.would和used to1）used to表示過去與現(xiàn)在或過去某時與后來的情況有不同，而would只表過去的情況。People used to think that the earth was flat.過去人們認(rèn)為地球是平的。（現(xiàn)在人們不這么認(rèn)為。）She would go out for a walk in the morning when she was in the country. 在鄉(xiāng)下時，她總是在早晨去散會兒步。（可能現(xiàn)在仍有散步的習(xí)慣。）2）used to可表示過去的習(xí)慣動作和經(jīng)常的情況，而would只表示過去的習(xí)慣動作。He used to would smoke while writing. 過去他寫東西時常抽煙。She used to be fat. 她過去很胖。1. I _ you, because I thought I must be wrong. A. dare not ask B. dare not to ask C. dare not asking D. dare to not ask2. There _ some flowers in the garden. A. were used to be B. used to be C. uses to be D. used to be having3. "_ I take it out?" "Im sorry, you _." A. Could .couldnt B. Might.might not C. Could.can D. May.cant4. You were stupid to climb the tree. You _ hurt yourself. A. may B. might C. will D. might have5. You _ those letters. Why didnt you ? A. should post B. should have posted C. must have posted D. ought to post.6. All the lights are on, the Smiths _ up. A. must get B. is getting C. must be getting D. would get7. He _ lead a horse to the water but he _ not make it drink. A. will.can B. may.can C. may.dares D. dare.can8. "Need we do this job now?" "Yes, _." A. you need B. you should C. you must D. you can9. _ to have lunch with us today? A. Do you likes B. Would you like C. Will you liked D. Have you liked10. He said that you _ watch TV all the evening if you wished. A. may B. must C. can D. might11. -Is John coming by train? -He should, but he _ not. He likes driving his car. A. must B. can C. need D. may12. Peter _ come with us tonight, but he isnt very sure yet. A. must B. can C. may D. will13. Michael _ be a policeman, for hes much too short. A. neednt B. cant C. shouldnt D. wont 14. I thought you _ be hungry, so I have brought you some cakes. A. may B. might C. can D. could15. I wonder how he _ that to the teacher. A. dare to say B. dare saying C. not dare say D. dared say16. Come on! We _ hurry because there isnt much time left. A. may B. must C. can D. need17. Amy did best in the English test. She _hard last week. A. must have working B. should have worked C. should work D. must work18. The fire spread through the hotel very quickly but everyone _ get out. A. had to B. would C. could D. was able to19. -I stayed at a hotel while in New York. -Oh, did you? You _ with Barbara. A. could have stayed B. could stay C. would stay D. must have stayed20. Its nearly seven oclock. Jack _ be here at any moment. A. must B. need C. should D. can