M4情態(tài)動(dòng)詞講解

1、PAGE PAGE 8M4U2Grammar-情態(tài)動(dòng)詞A. 特征特征情態(tài)動(dòng)詞有一定詞義，但不完全，不能單獨(dú)作謂語，須和不帶to的動(dòng)詞不定式（ought等除外）一起構(gòu)成合成謂語；情態(tài)動(dòng)詞沒有人稱和數(shù)的變化；情態(tài)動(dòng)詞表示可能，能力，允諾，命令，愿望，敢于等情態(tài)。B. 基本形式原形過去式cancouldmaymightmustmust (or: had to)ought toought towillwouldshallshouldneedneeddaredaredC. 情態(tài)動(dòng)詞和否定詞not連用時(shí)的簡(jiǎn)略形式情態(tài)動(dòng)詞not簡(jiǎn)略形式例句can notcant不能 不可能He cant ski. 他不會(huì)滑

2、雪。He cant be in the classroom. He is in the library.could notcouldnt不能;不可能I couldnt speak English fluently then.may not可能不He may not be at home, Im not sure.must notmustnt 禁止，不允許You mustnt think only of yourselves.你們不能只想自己。should notshouldnt不該，不應(yīng)當(dāng)We shouldnt be so careless. 我們不應(yīng)當(dāng)這樣粗心大意。ought toought

3、nt不該，不應(yīng)當(dāng)，理該不There oughtnt to be much noise in a library.圖書館里不該喧鬧。will notwont 不愿意I wont do so. 我不愿這樣做。would notwouldnt不愿意He wouldnt go to bed before he finished his homework.他在完成作業(yè)以前不愿睡覺。shall notshant 不得，不該You shant leave your post. 你不得離開崗位。need notneednt 不必；沒必要You neednt go there alone.你不必單獨(dú)去那里。da

4、re notdarent 不敢She darent swim in a river. 她不敢在江河游泳。D. 情態(tài)動(dòng)詞的用法can /could 的用法：用法例句表示能力1. My daughter can speak three languages quite well: Chinese France and English. 我女兒能流利地講三種語言：中文、法文和英文。2. Because he was tired, he couldnt swim across the river. 表示表示可能性1)肯定句中表“有時(shí)會(huì)，可能會(huì)”； 2)否定句中表“不可能”3) 疑問句中，只能用can,

5、could 表可能性1. If we dont have a guide, we can lose our way in the forest2. We have just bought 50kg of rice. We cant be in short of food. 3. Doing exercise alone in the gym can be very dangerous.4. Can he come back tonight?5. Could the boy have been lost in the big city?表示請(qǐng)求，命令，驚訝等1. Can you lend me

6、your bike? 你能將自行車借給我嗎？2. You can bring the calculator tomorrow. 明天你們要帶計(jì)算器來。3. How can he be so rude? 他怎能這樣無禮?Could用于疑問句中表請(qǐng)求，語氣較委婉，但肯定回答時(shí)用can，而不用could。1. Could you lend me your book? Certainly, I can.2. Could you let me have your pass? 看看你的通行證好嗎？說明can 和be able to都可以表示能力，但它們的過去式在意義上有點(diǎn)差別，could偏重于表示某人過去

7、有某種能力，但并不明確表示某人干了某事，而was/were able to 則表示過去某人有能力干某事，實(shí)際上干了某事。另外，be able to 有更多的時(shí)態(tài)形式。如：I was able to (managed to) finish my homework in an hour.2. Chuck has been able to realize that friendship is about feelings and we must give as much as we take. 查克能夠明白這樣的道理：友誼就是感情，我們既要得到關(guān)愛，又須給與別人同樣多的關(guān)愛。may/might的用法

8、：用法例句表示允許和請(qǐng)求might在語氣上更委婉。注意疑問句的回答。1. You may use my camera. 你可以用我的攝像機(jī)。2. May /Might I come in? Sure. 我可以進(jìn)來嗎？當(dāng)然可以。 May / Might I watch TV after finishing my homework? Yes, you may. / No, you mustnt. / No, you may not. / No, youd better not. 表示可能性1. She may not be free today. 今天她可能沒有空。2. He might come

9、 to see you this evening. 今晚他可能來看你。用在由so that或in order that引導(dǎo)目的狀語從句中1. She saved her money in order that she might buy a watch.為了買塊手表，她節(jié)省錢。2. I am saving my money so that I may go to Australia next winter.我正在攢錢，以便明年冬天到澳大利亞去。表示祝愿1. May you have a good time / 2. May you succeed.表示讓步Try as he may, he c

10、annot find her.表示建議（和as well連用）1. We may / might as well stay where we are.2. You may / might as well consult a dictionary.Must 的用法：用法例句表示必須，必要，mustnt (must not) 表示禁止，不準(zhǔn)1. You must come to school early enough for the morning class. 你必須早晨到校上早讀課。2. You mustnt talk to your father like that. 你不能那樣對(duì)你父親講話

11、。表示主語的肯定推測(cè), “一定”“準(zhǔn)是”，比may肯定得多;后面加動(dòng)詞不定式的完成式表示對(duì)過去事物的推測(cè)后面加動(dòng)詞不定式的進(jìn)行式表示對(duì)現(xiàn)在進(jìn)行事物的推測(cè)1. The lady cant be only 30. She must be 50. 2. The old man must be our history teacher. 3. Mike speaks Chinese very well. He must have studied Chinese before. 4. She must be waiting for us, isnt she? 5. You must have seen t

12、he film, havent you?6. You must have seen the film last week, didnt you?7. His parents may have beaten him, havent they?8. His parents cant have beaten him yesterday, did they?9. He must have finished reading the novel by yesterday, hadnt he?10. Your mother must have been told the truth just now, wa

13、snt she?用于if從句中，表“一定要，非得要”Ill tell you the truth, if you must. 表示推測(cè)的否定和疑問結(jié)構(gòu)不能用must須用can1. The door is locked; she cannot be at home. 門鎖了，她一定不在家。2. Can the news be true? 這消息可能是真的嗎？說明must 和have to 都可以表示必須，但must 著重說話人的主觀看法，而have to強(qiáng)調(diào)客觀需要。 另外，have to 有多種時(shí)態(tài)形式。如：1. We must learn at least a foreign languag

14、e well. 我們必須學(xué)好至少一門外語。2. Mother was ill, so I had to look after her at home. 母親病了，我得在家照顧她。will/would的用法:用法例句用于各種人稱，表示意愿、意志或決心; 可用于if條件句中1. I will do anything my country asks me to do.我決心做祖國(guó)需要我做的任何事。2. Xiao Hong said that she would help me with my maths. 3. If you will listen to me, Ill give you some

15、advice on how to learn English 用于第二人稱的疑問句，表示征求對(duì)方的意見或向?qū)Ψ降恼?qǐng)求。Would 比will更委婉客氣些1. Will you give this note to Tom as soon as he comes back? 湯姆一回來，你把便條給他，好嗎？2. Would you mind explaining it again?請(qǐng)你能再解釋一遍好嗎？will表示現(xiàn)在的某種傾向或習(xí)慣。 Would 表示過去習(xí)慣發(fā)生的動(dòng)作1. Fish will die without water. 沒有水魚就會(huì)死。2. They will have a part

16、y every Saturday evening.3. He would go for a walk every evening when he stayed at the hotel. 當(dāng)他位住在旅館的那段時(shí)間，他有每天傍晚散步的習(xí)慣。would like“愿意，要”1. I would like to hear your opinions. 我愿意聽聽你的意見。2. Would you like to have a chat with me? 你愿不愿意和我一起聊天？would rather “寧愿，較喜歡”1. I would rather stay at home than go to

17、 the cinema.2. He would rather have tea. 他喜歡茶。3. I would rather not go to the concert. 我寧愿不去參加音樂會(huì)。說明would 和used to 都表示過去的習(xí)慣，但used to 表示這種習(xí)慣現(xiàn)在已停止，used to 后面可用狀態(tài)動(dòng)詞或動(dòng)作動(dòng)詞，而would后只能用動(dòng)作動(dòng)詞。 1. I used to smoke heavily, but I dont any more.2. He would go to see his grandfather on Sunday when he was in middle

18、 school. 他中學(xué)時(shí)星期天常去看望祖父。3. Ben used to be a heavy smoke. 本曾經(jīng)是一桿老煙槍。shall/should 的用法：用法例句Shall (表示說話者的意圖、許諾、警告、命令、決心等，用于陳述句第二、三人稱中) 必須，應(yīng)1. You shall not leave your post. 你不得離開崗位。（命令）2. You shall see her again before long. 不久你就會(huì)見到她。（允諾）3. You shall go to the front at once(命令)4. Dont worryYou shall get

19、the answer this very afternoon（允諾） 5. He shall be sorry one dayI tell you(警告)6. Nothing shall stop us from fighting against pollution(決心)shall (表示強(qiáng)烈意志和不可避免性，用于陳述句第一、第三人稱) 一定1. We shall have to be ready.我們一定得準(zhǔn)備好。2. He is determined that nothing shall stop him. 他已下定決心什么也阻擋不了他。shall (在條約、規(guī)章、法令等文件中表示義務(wù)或

20、規(guī)定，一般用于第三人稱) 應(yīng)，必須The new regulation shall take effect on June 1st.新章程自6月1日起施行。The shares of the company shall be divided among the family members.這家公司的股份應(yīng)在該家族成員間分配。shall (在問句中表示征求對(duì)方意見，主要用于第一、第三人稱) 好嗎？要不要？1. Shall I close the door? 要不要我把門關(guān)上？2. Lets go to the cinema, shall we? 我們?nèi)タ措娪昂脝幔?. Shall I /we

21、/ he / she / they / Tom / Rose / my brother go to the concert with you this evening？ (征求意見)should（表示義務(wù)責(zé)任）應(yīng)當(dāng)，應(yīng)該should have done含責(zé)備之意1. You shouldnt be so careless.你不應(yīng)該這樣粗心大意。2. He should have told me the news earlier.他本來應(yīng)該早些告訴我這消息。should（表示語氣較強(qiáng)的假設(shè)）萬一, 竟然1. If he should fail to come, ask Jack to work

22、in his place. 2. Should it rain tomorrow (或If it should rain tomorrow), the meeting would be postponed. 萬一明天下雨，會(huì)議就延期。should（表示可能性、推測(cè)、推論）可能, 理該1. They should have arrived in Beijing by this time. 他們這是該已到北京了。2. The report is written after careful investigation, so it should be reliable. 這份報(bào)告是經(jīng)過周密調(diào)查寫成的

23、，所以該是可靠的。should（表示委婉、謙遜）可, 倒1. I should like to have a talk with you. 我想跟你談一談。2. You are mistaken, I should say. 據(jù)我看，你可搞錯(cuò)了。should（用于表示必要、適當(dāng)、驚奇、遺憾等的從句中）應(yīng)該；竟然會(huì)1. It is proper that no hasty decision should be made. 不應(yīng)當(dāng)做出匆促的決定。2. It is astonishing that we should find violence here. 我們這兒竟然有暴力行為，真令人震驚。sho

24、uld (用于表示建議、命令、決定等的從句中)應(yīng)該, 必須1. He suggested that we should make better use of the school library.他建議我們應(yīng)該更好地使用學(xué)校圖書館。2. The young doctor proposed that he should try the experiment on himself. 青年醫(yī)生建議在他自己身上做實(shí)驗(yàn)。ought to 的用法用法例句should/ ought to 都表示義務(wù)、責(zé)任。ought to 的語氣要更強(qiáng)一些1. You ought to be attentive at cl

25、ass. 你在課上應(yīng)當(dāng)思想集中。2. He oughtnt to be so careless in his work. 他在工作中不應(yīng)該如比粗心大意。ought to have done表示過去該做而未做的事，ought not to have done則表示一件不該做的事情發(fā)生了1. I ought to have washed my clothes last night.我昨晚就應(yīng)當(dāng)洗衣服了。2. You oughtnt to have wasted so much time.你不該浪費(fèi)這么多時(shí)間。need/dare 的用法：用法例句need作情態(tài)動(dòng)詞常用于否定句或疑問句中，做實(shí)義動(dòng)詞不

26、受限制1. -Need I go with you to the market? ( 情態(tài)動(dòng)詞) -No, you neednt. Ill manage all by myself. / Yes, you must. 2. Tom doesnt need to come to the meeting tomorrow. (實(shí)義動(dòng)詞)湯姆不必明天來參加會(huì)議。 need后面跟動(dòng)詞不定式的完成式，用在否定句中，表示做了本來不必做的動(dòng)作Your elder brother need not have come last night. 你哥哥昨天晚上本來無需來的。need not have come指來

27、了，但實(shí)際不必來did not need to come則表示不必來，實(shí)際上沒有來dare作情態(tài)動(dòng)詞常用于否定句或疑問句中，做實(shí)義動(dòng)詞不受限制1. The girl dare not go out at night. （情態(tài)動(dòng)詞） 2. Dare you climb such a steep cliff? 3. He doesnt dare to cross the river.（實(shí)義動(dòng)詞）4. How dare you say Im unfair?情態(tài)動(dòng)詞have done用法例句表推測(cè)時(shí)：(表陳述)may/might have done（語氣不肯定）過去可能做了某事cant/couldnt

28、 have done sth.（語氣肯定）過去不可能做了某事must have done sth.（語氣肯定）過去一定是發(fā)生某事了should have done sth. 應(yīng)該已做完某事；竟然做了某事（表驚訝）1. I didnt see Mary at the meeting yesterday. She might have been ill, I guess.2. The streets are all dry. It couldnt have rained during the night.3. The streets are all wet; it must have rained

29、 during the night.4I hardly imagine such a gentleman should have been so rude to the old lady.5. They should have arrived in Beijing by this time.表責(zé)備時(shí)：（表虛擬）might have done sth.過去本可能做而未做could have done sth.過去本能做而未做should have done sth.過去本該做而未做ought to have done sth.過去本應(yīng)該做而未做neednt have done sth.過去本不必

30、做卻做了1. He might have given you more help, even though he was very busy.2. Did you listen to the speech? No, we could have attended it. But we had a lot of traffic on our way.3. The plan is dead. Maybe I should have given more water.4. Your brothers failed in English again. You ought to have given hi

31、m more help.5. Mr. Smith didnt come last night, did he? No. We neednt have waited for him. A whole night was wasted.表意愿時(shí)：（表虛擬）would have done sth.想做而未做，本可以做而未做would like to have done sth. 想做而未做would rather have done sth.寧愿做某事而未做1. If you had come five minutes earlier, you would have seen the famous

32、star. 2. I would like to have gone to your help, but I was too busy.3. The film was a bore. I would rather have stayed at home.語法練習(xí)一、單項(xiàng)選擇1. You didnt go to the party yesterday, or I _ you. A. would seeB. could seeC. might have seenD. might see2. He _ at the meeting this morning. He was in hospital t

33、hen.A. cant have spokenB. mustnt have spokenC. shouldnt have spokenD. neednt have spoken3. He must be in the classroom, _ he?A. cantB. mustnt heC. isntD. neednt4. You _ have brought your camera. They all had theirs with them.A. couldntB. neednt C. wouldntD. mustnt5. My little son _ out alone at nigh

34、t. A. dares not goB. dares not to goC. dare not to goD. doesnt dare to go6. At last he _ finish the work ahead of time.A. couldB. was able toC. could be able toD. can be able to7. There must be some soldiers hidden in the forest. _ any behind the church?A. Must there beB. Should there beC. May there beD. Can there be8. If anybody _ to see me, say that I shall be back soon.A. would be comeB. comesC. cameD. should come9. Could I have a word with you?- Yes, _.A. you canB. you couldC. you mustD. you should10. I told him how to get here, but perhaps I _ for him.A. had to draw a mapB. sho