一.情態(tài)動詞的定義: 情態(tài)動詞表示說話人對某一動作或狀態(tài)的態(tài)度,即表示說話人的某種感情或語氣.表示”需要”可以”必須”應(yīng)當(dāng)”等意義. 二.情態(tài)動詞的特征:n 1.不能單獨(dú)作謂語,除ought to, have to和used to以外，后面只能接不帶to的不定式；n 2.沒有人稱和數(shù)的變化。有些情態(tài)動詞沒有過去式，如must;有些有過去式，如;n can-could may-might shall-should n will-would have to-had ton 3.情態(tài)動詞的否定式一般是在它們的后面加否定詞not構(gòu)成; 情 態(tài) 動 詞 表 示 推 測不 表 示 推 測can couldmay mightshall shouldmust will wouldought tohave to dare (darent)need (neednt) used to 三.情態(tài)動詞的用法歸納:n (一).can/could:n 1.表示能力，常譯為“能,會”:n eg.(1).I can speak Japanese, but I cant write itn (2).Some of us can use the computer now, but we couldnt 10 years ago. n 2.表示許可,常譯為”可以”;could可以表示更加委婉的請求：n eg.(1).Can/Could I have a look at your photos?n (2).You can smoke in this room. can/be able to辨析：n 1.從時態(tài)上:can只有現(xiàn)在時和過去時，而be able to則有更多形式.在將來時,完成時和非謂語動詞結(jié)構(gòu)中只能用be able ton 2.從意義上:can一般指理論上具備做一件事的能力，而be able to則表示設(shè)法做成某事，相當(dāng)于manage to do或succeed in doing n eg.(1).The young man couldnt carry the big stone(指不具備能力)n (2).This time I failed in the exam, but Ill be able to pass the exam next time.(指設(shè)法做到)n =Ill succeed in passing the exam next time. 1 A computer _ think for itself; it must be told what to do. A. cant B. couldnt C. may not D. might not2. The fire spread through the hotel very quickly but everyone _ get out. A. had to B. would C. could D. was able toA D 3. They will _ run this machine on their own in three months.A. can B. could C. may D. be able to4. That big cinema _ seat 2,000 people.A. can B. should C. ought to D. is able to D A n (二).may/might:n 1.表示許可或在疑問句中征詢對方許可，常譯為“可以”.表示征詢許可時,may可與can/could換用；might比may的語氣更委婉一些.對其一般疑問句的肯定回答可用may或can,但否定回答時要用mustnt或cant. mustnt表示“不可以”n“禁止”之意. n eg.(1).You may go home now.n (2).May/Might I have a word with you?n (3).-May I come in?n -Yes, you may/cann -No, you cant/mustntn -_I take the book out? n -Im afraid notn A. Will B. May C. Must D. Need 1. Could I borrow your dictionary? Yes, of course you _.A. might B. will C. can D. should2. Might I watch TV after supper? Yes, you _. A. may B. must C. might D. couldC A n 2.may常用于祈使句中，表示祝愿:n eg.(1).May you succeed 祝您成功!n (2).May God bless you愿上帝保佑你！n (三).must/have to:n 1.表示“必須”時,must表示說話人的主觀看法，而have to表示客觀需要,因而常譯為“不得不；只好”講n eg.(1).I dont like to stay here any longer; I must leave now n (2).Its too late. I have to leave now n 2.常用have to的相應(yīng)形式表示現(xiàn)在,過去和將來“必須”做某事.have got to是have to的口語形式.have to前可以用情態(tài)動詞，而have got to則不能,即不能說will/shall/may have got ton eg.(1).I had to make money to support my familyn (2).I will have to learn how to use a computer n 3.have to的疑問式為:Do/Does/Did+主語+have to? have to的否定式是”do/does/did not (dont/doesnt/didnt) +have to”,表示沒有義務(wù)或必要做某事,意為”不必”,?？梢曰卮餸ust提問的疑問句,而must的否定式mustnt表示禁止,意為”不得,一定不要”n eg.(1).Do you have to go now?n (2).Take your time. You dont have to do it at once. n 4.must的否定式為must not/mustnt時意為“不許,禁止”,而need not/neednt意為“不必”n eg. Must I come back before ten?n -Yes, you must (No, you neednt/dont have to)n 5.must意為“偏要,偏偏”時,指做令人不快的事情n eg.(1).Must you shout so loudly?n 你非要那么大聲嗎？ n (2).Why must it rain on Sunday?n為什么偏偏在星期天下雨？ n 1.I have told you the truth. _I keep repeating it?n A. Must B. Can C. May D. Willn 2.You_park here! Its an emergency exitn A. wouldnt B. neednt C. couldnt D. mustntn 3.You_buy a gift, but you can if you want ton A. must B. mustnt C. have to D. dont have to n (四).shall/shouldn 1.shall用于第一,三人稱的疑問句中,表示說話人征求對方的意見或向?qū)Ψ秸埵緉 eg. When shall we begin our supper?n 2.shall用于第二,三人稱,表示說話人給對方的命令,警告,允諾或威脅n eg.(1).You shall go with me.(命令)n (2).You shall fail if you dont work harder.(警告) n (3).He shall read the book when I finish reading.(允諾) n 3.should除基本用法“有責(zé)任或義務(wù)做某事”外,還表示勸告,建議,命令,其同義短語是ought to.在疑問句中,通常用should代替ought to,意為”應(yīng)該”n eg.(1).You should go to class right awayn (2).Should I open the window?n 4.should+have+done表示應(yīng)該做而實(shí)際上沒有做n eg. You should have handed it in earlier n n shouldnt+have+done表示不應(yīng)該做而實(shí)際上卻做了n eg. You shouldnt cheat in the exam. n -I havent got the reference book yet, but Ill have a test on the subject next monthn -Dont worry. You_have it by Fridayn A.could B.shall C.must D.may n (五).will/wouldn 1.表示請求,建議,用于第二人稱疑問句中,would比will委婉客氣n eg. Would you pass me the book?n 2.表示意志,愿望和決心,有“愿,要”之意.would表示過去的意愿和決心n eg. I will never do that again n (六).would/used ton 兩者均表示“過去常?！?但would僅表示過去的習(xí)慣性動作,現(xiàn)在有可能還如此,也有可能不再那樣;used to既表示過去的動作也表示過去的狀態(tài),不過現(xiàn)在不再做或不再有那種狀態(tài),強(qiáng)調(diào)與現(xiàn)在的對比n eg.1.He would get up at 8(現(xiàn)在可能還這樣)n 2.He used to get up at 8(現(xiàn)在不這樣了)n Xiao Li used to be a worker, but he is now a university student n (七).ought to/ought not ton 1.ought to”應(yīng)當(dāng);應(yīng)該”,只有一種形式,沒有人稱和時態(tài)的變化.它可以表示”有義務(wù)或責(zé)任”做某事,語氣比較強(qiáng),還可以表示”建議或勸告”.n eg.Humans ought to stop polluting naturen 2.同should一樣，ought to后跟動詞不定式的完成式,其肯定句表示”過去本應(yīng)該做某事而未做”;其否定句則表示”過去不該做某事卻做了”. n eg.(1).You ought to have come here earliern (2).You oughtnt to have opened the letter!It wasnt for you n 3.ought to的否定形式為ought not to或oughtnt to,其一般疑問句形式是將ought置于主語前n eg.(1).You oughtnt/ought not to blame himn (2).-Ought I to go?n -Yes,you ought ton 4.在反意疑問句中,下面兩種形式都可以:n eg.Bob ought to be at home now,shouldnt/oughtnt he? n 5.ought to/shouldn一般說來,兩者可換用,只是ought to語氣略強(qiáng).另外,表示出于法令規(guī)則,行為準(zhǔn)則,道德責(zé)任等客觀情況而”應(yīng)該”做某事時,一般應(yīng)用ought to;若用should則含有個人意見,強(qiáng)調(diào)主觀看法.n eg.(1).You are his father.You ought to take care of himn (2).We should not use too many big words in our everyday speech n (八).need/needntn 1.need”需要,必要”,既可作情態(tài)動詞,也可作實(shí)義動詞n (1).用作情態(tài)動詞,后接動詞原形,沒有人稱和數(shù)的變化n eg.a.Need I do it at once?n b.Theres plenty of time.We neednt drive so fastn (2).用作實(shí)義動詞時,有動詞的各種形式變化 n need+n./doing/to do n eg.a.He needs our helpn b.We dont need to tell him the truthn c.The bike needs repairing=The bike needs to be repairedn need doing=need to be done(主語與do之間為動賓關(guān)系)n need to do(主語與to do之間為主謂關(guān)系) n 2.neednt have done表示“本來不必做某事卻做了”n eg.You neednt have told me the newsn 3.以need開頭的疑問句的否定回答可用neednt,但肯定回答常用Yes,I mustn eg.-Need you go now?n -Yes,I must/No,I neednt n (九).used to/be used to do/be used to doingn 1.used to表示”過去常常,過去是”,沒有人稱和數(shù)的變化.其否定形式為usednt to或didnt use to.其一般疑問句形式是將used提到主語前或用Diduse to結(jié)構(gòu)n eg.Did she use to be a doctor?n 2.be used to do sth.表示“被用來做某事”n eg.The wood here will be used to make a house n 3.be used to doing sth.表示習(xí)慣于做某事n eg.I am already used to the noisy city life heren (十).had better的用法n had better主要用來表示勸告或建議,其后跟動詞原形,意為“最好”n had better(not)do n eg.Youd better try it again if you fail this time n (十一).would rather的用法n would rather 意為“寧愿”,表示選擇,后接不帶to的不定式n eg.Which would you rather do, go to cinema or stay at home?n (十二).dare的用法n dare既可以作情態(tài)動詞,也可以作實(shí)義動詞,意為“害怕” n 1.用作情態(tài)動詞,后接動詞原形,沒有人稱和數(shù)的變化n 2.用作實(shí)義動詞,用”dare to do”結(jié)構(gòu)n三.情態(tài)動詞表推測的特殊用法n 1.can/could表示對現(xiàn)在或過去情況的推測,只用于疑問句或否定句中n eg.(1).Can what he said be true?n (2).He cant be theren用于肯定句中,表示理論上的可能性 n eg.Accidents can happen at any time n 2.may/might表示對現(xiàn)在或過去情況的推測,多用于肯定句和否定句中.may not表示“可能不”之意;might比may可能性小n eg.He may be very busy nown 3.must表推測時,只能用于肯定句中,意為“一定,肯定”n must+do 對現(xiàn)在或經(jīng)常發(fā)生的事作肯定的推測n must+have done 對過去事實(shí)或情況的肯定推測 n must+be doing 對正在發(fā)生的事作肯定推測 n此時，must的否定形式不是mustnt,而是cant/couldntn cant/may/must+don cant/may/must+have donen cant/may/must+be doingn對比:could have done”過去能做某事而沒做”n 4.should表示推測.這種推測往往有一定的根據(jù),含有“按道理應(yīng)該”之意n eg.If the train is on time,she should arrive in Beijing by seven 在不表示推測的情態(tài)動詞中, 我們要注意以下考點(diǎn):1. 表示能力、許可的情態(tài)動詞的用法。2. 表示否定的情態(tài)動詞的用法。3. shall 和 will 的多種意義的區(qū)別。4. 情態(tài)動詞短語的使用。5. 虛擬語氣中情態(tài)動詞的使用。 I darent ask her for a rise. 我不敢請求她加薪.How did you dare to tell her that? I wonder whether he dare stand up in public. I dont know how she dares to wear that dress. Do you need any help?I wonder whether he need send it immediately.I need hardly tell you that the work is dangerous.The garden doesnt need watering at the moment.You neednt finish that work today. 可兼做行為動詞的情態(tài)動詞：need 、 dare 情態(tài)動詞 (+動詞原形)行為動詞 .needdare 1.無 人 稱 和 數(shù) 的 變 化 ; 2.尤 其 用 于 ：*否 定 句 及 疑 問 句 中 ;*在 if/whether之 后 ;*或 與 hardly, never, no one, nobody連 用 ; 3.常 以 needn t 和daren t 的 形 式 出 現(xiàn) ;4.dare有 其 過 去 時 dared. 多用于肯定句; (sb.) need to do dare to do(sth.) need to be done (sth.) need doing 判斷正誤: How dare you say such a thing? How dare you to say such a thing?He darent to speak English before such a crowd, did he?He darent speak English before such a crowd, dare he? 表 示 推 測 情 態(tài) 動 詞 的 重 要 用 法 .1. You must be Mr Smith-I was told to expect you here.2. He must have known what we wanted.3. We may have read the same report.4. He cant have slept through all that noise.5. Theres someone outside-who can it be? 2. 表示否定的情態(tài)動詞的用法: 部分情態(tài)動詞的否定式是情態(tài)動詞中的考點(diǎn)之一。 mustnt 不準(zhǔn), 禁止 neednt 沒必要 ( = dont have to )cant 不能; 不可能may not 不可以; 可能不shouldnt 不應(yīng)該 ( = ought not to ) 1. You _ return the book now. You can keep it till next week if you like. A. cant B. mustnt C. neednt D. may not2. Johnny, you _ play with the knife, you _ hurt yourself. A. wont ; cant B. mustnt ; may C. shouldnt ; must D. cant ; shouldntC B 3. -Will you stay for lunch? -Sorry, _. My brother is coming to see me. A. I mustnt B. I cant C. I neednt D. I wont4. -May I pick a flower in the garden? - _. A. No, you neednt B. Not, please. C. No, you mustnt D. No, you wontB C 4. 情態(tài)動詞短語的使用:would like to dowould rather dowould rather + 從句would prefer to do.had better do. 改錯:1. Would you like having some tea?2. Id prefer going to the lecture this evening.3. Id rather you to go to the meeting.4. He would rather to die than to give in.5. Youd better to have your hair cut today.Would you like to have some tea?Id prefer to go to . you went to .He would rather die than give in.Youd better have .