情態(tài)動(dòng)詞的用法歸納1

1、情態(tài)動(dòng)詞的用法要點(diǎn)一 can和could情態(tài)動(dòng)詞用法例句can/could表示能力1“I dont think Mike can type.” “Yes, he can.”2I can speak fluent English now , but I couldnt last year.在肯定句中，表示客觀可能性，并不涉及具體某事會(huì)發(fā)生，常用來(lái)說(shuō)明人或事物的特征。要表達(dá)具體某事實(shí)際發(fā)生的可能性時(shí)，不用can，需用could，may，might。1 As a human being, anyone can make a mistake.2 Im confident that a solution

2、 can be found.3 He can be very forgetful sometimes.4 I may stay at home this weekend.（實(shí)際可能性）5 Peter might come to join us.(實(shí)際可能性) 6 It will be sunny in the daytime ,but it could rain tonight.(實(shí)際可能性)表示請(qǐng)求和允許。表示請(qǐng)求，口語(yǔ)中常用could代替can，使語(yǔ)氣更委婉。1 Can we turn the air conditioner on?2 Any police officer can insi

3、st on seeing a drivers license.3 In soccer, you cant touch the ball with your hands.4 Could you have her call me back when she gets home, please?5 I wonder if I could just ask you to sign this.表示對(duì)現(xiàn)在的動(dòng)作或狀態(tài)進(jìn)行主觀的猜測(cè)，主要用在否定句和疑問(wèn)句中。1 It cant be easy caring for a man and a child who are not your own.2 Can t

4、he man over there be our head master?表示驚異、懷疑、不相信等態(tài)度，主要用在否定句、疑問(wèn)句和感嘆句中。1 Can this be an excuse for not giving them help?2 This cant be true.3 How can you be so crazy.特別說(shuō)明：（1） could用來(lái)表示請(qǐng)求時(shí)，語(yǔ)氣委婉，主要用于疑問(wèn)句，不能用于肯定句，答語(yǔ)應(yīng)用can（即：could不能用于現(xiàn)在時(shí)態(tài)的簡(jiǎn)略答語(yǔ)中）。如：Could I use your dictionary?Yes, you can.(否定回答可用：No, Im afra

5、id not.)(2) can和be able to辨析can(could)和be able to都可以表示能力，意思上沒(méi)有區(qū)別。但can只有現(xiàn)在式和過(guò)去式，而be able to則有更多的形式。如：Ive always wanted to able to speak fluent English.Those bags look really heavy, are you sure youll be able to carry them on your own?但是，表示在過(guò)去某時(shí)的某一場(chǎng)合經(jīng)過(guò)一番努力，終于做成了某事，通常不用could，而用was/were able to來(lái)表示。這時(shí)，wa

6、s/were able to相當(dāng)于managed to do或succeed in doing。如：After the accident it was a long time before she was able to walk again.The fire was very big, but most people were able to escape from the building.(3) 慣用形式“cannot too”表示“無(wú)論怎么也不（過(guò)分）”。如： You cannot be too careful.你越小心越好。 慣用形式“cannot but+ 不定式（不帶to）”表示

7、“不得不，只好”。如： I cannot but admire her determination.我不得不欽佩你的決心。 二may和 might情態(tài)動(dòng)詞用法例句may/might表示允許、許可。否定回答一般用must not/mustnt,表示“禁止、阻止”之意，但也可以用had better not (最好別)或may not（不可以），語(yǔ)氣較為委婉。1 May I come in and wait?2 May I smoke here?No, you mustnt(或No, youd better not.)在表示請(qǐng)求、允許時(shí)，might比may語(yǔ)氣更委婉些。用May I征詢(xún)對(duì)方許可在文

8、體上比較正式，在口氣上比較客氣，在日常用語(yǔ)中，用Can I征詢(xún)對(duì)方意見(jiàn)更為常見(jiàn)。1 Might I borrow your pen?2 I wonder if I might speak to your son.表示可能性的推測(cè)，通常用在肯定句和否定句中，含有“或許”“大概”“可能”之意；用might代替may時(shí)，則語(yǔ)氣顯得更加不肯定。1 It may rain this afternoon.2 She might come to join us this afternoon.3 I suppose he might have missed the train.may用于祈使句表示祝愿1 Ma

9、y you succeed.2 Long may he live! 愿他能持續(xù)住下去。3 May you have many more days as happy as this one.4 May she rest in peace.愿她安息。慣用句式：“may well+ 動(dòng)詞原形”，意為“完全能，很可能”，相當(dāng)于to be very likely to“may as well或might(just)as well+動(dòng)詞原形”意為“最好，滿可以，倒不如”，相當(dāng)于“had better或there is no reason to do anything else.1 It may well

10、change forever the way you look at Greek art.2 There may well be a real problem here.3 There is nothing to do, so I may as well go to bed.4 You may as well tell us now, well find out sooner or later.5 I suppose we might as well go home.6 And if you have to plough the field anyway, you might as well

11、plant it at the same time.二must和have to情態(tài)動(dòng)詞用法例句must表示“必須，應(yīng)該”之意，語(yǔ)氣比should，ought to強(qiáng)烈。其否定形式mustnt表示“不準(zhǔn)，不應(yīng)該，禁止”等意1 You must come to school on time.2 Everybody must obey the law.3 You mustnt drive so fast in the street.4 We mustnt waste any more time.在回答帶有must的問(wèn)句時(shí)，否定回答常用neednt或dont have to，表示“不必”，而不用mus

12、tnt1Must I come back before ten? Yes，you must.(No, you neednt)表示有把握的推測(cè)，意為“一定、準(zhǔn)是、相必”，只用于肯定句中1 It must be my mother.2 You must be hungry after a walk.3 There must be a hole in the wall. have tohave to“必須，不得不”，意義與must相近。但must表示的是說(shuō)話人的主觀看法，而have to則往往強(qiáng)調(diào)客觀需要。1 The film is not interesting. I really must go

13、 now.2 I have to go now, because my mother is in hospital.must只有一種形式，即現(xiàn)在式與過(guò)去式都是一種形式，而have to則涉及各種人稱(chēng)、時(shí)態(tài)等方面的變化形式。1I had to work hard when I was your age.2I will have to learn how to use a computer.3In order to take the exam, well have to finish the whole book by the end of this month .兩者的否定意義不同，mustnt

14、表示“禁止，不許”，dont have to表示不必。1 You mustnt go there.2 You dont have to go there.四shall和should情態(tài)動(dòng)詞用法例句shall用于第一、二、三人稱(chēng)構(gòu)成的疑問(wèn)句，表示征求對(duì)方意見(jiàn)或請(qǐng)求指示1 Shall I open the window?2 Shall we say 6 oclock, then?3 What shall I get for dinner?用于第二、三人稱(chēng)陳述句中，表示說(shuō)話人給對(duì)方的命令、警告、允諾或威脅。1 Dont worry, you shall get the answer this aft

15、ernoon.(允諾)2 He shall be sorry for it one day, I tell you. （警告）3 You shall do as I say. (命令)4 If you children dont do as I tell you, you shall not go to the party. (威脅) should表示勸告或建議，意為“應(yīng)該”1 What should I do?2 Should I trust him?3 You should read his new book.表示推測(cè)，用在肯定句中，對(duì)現(xiàn)在的情況或可能發(fā)生的事的主觀推測(cè)或期待。意為“想必，

16、大概，或許”1 It should be a nice day tomorrow.2 Try phoning Robert, he should be home now.3 He should be around sixty years old.還可以用在if引導(dǎo)的條件句中，表示一件事聽(tīng)起來(lái)可能性很小，但也不是完全不可能，相當(dāng)于“萬(wàn)一”的意思。從句謂語(yǔ)用should+動(dòng)詞原形構(gòu)成，主句都一定用虛擬語(yǔ)氣1 Ask Tom to ring me up if you should see him. (你萬(wàn)一見(jiàn)到湯姆，請(qǐng)讓他給我打個(gè)電話)2 Should I be free tomorrow, Ill

17、 come. (萬(wàn)一我明天有時(shí)間，我就過(guò)來(lái))3 If things should change suddenly, please let me know. (萬(wàn)一情況突變，請(qǐng)通知我)用于疑問(wèn)句或感嘆句中，表示意外、驚異的情緒，意為“竟會(huì)”，與why，what，how，who連用，如果是疑問(wèn)句，則不需要回答。1 Why should anyone want to marry Tony?2 Dont ask me. How should I know?五will和would情態(tài)動(dòng)詞用法例句will/would用于表示意志或意愿。will指現(xiàn)在，would指過(guò)去。1 He is the man wh

18、o will go his own way. (他首歌自行其是的人。)2 They said they would meet us at 10:30 at the station.表示請(qǐng)求、建議等，用would比用will委婉、客氣。1 Will you please take a message for him?2 Would you please tell me your telephone number?表示習(xí)慣或傾向，意為“總是，慣于”。will至現(xiàn)在，would指過(guò)去。1 Fish will die without water.2 People will talk. (人們總會(huì)說(shuō)閑話

19、。)3 When we worked in the same office, we would often have coffee together.表示推測(cè)，意為“很可能，大概”。will表示推測(cè)比should把握大，比must把握小。1 These things will happen.2 That will be the messenger ringing.3 It would be about ten oclock when he left home.表示功能，意為“能，行”。慣用形式：will do/would do表示“解決問(wèn)題”、“就行”。1 That will be all r

20、ight.2 Either pen will do.3 It would not do to work too late.（工作太晚不行。）用于否定句中，意為“不肯”、“不樂(lè)意”1I wont listen to your nonsense.2No matter what I said, he wouldnt listen to me.特別說(shuō)明：would與used to辨析would可用來(lái)表示過(guò)去反復(fù)出現(xiàn)的動(dòng)作，但不能表示過(guò)去存在的狀態(tài)，所以我們不能說(shuō)：“she would be a quiet girl.”另外，would強(qiáng)調(diào)過(guò)去某種特定情況下的活動(dòng)，是完全過(guò)去的事情，同現(xiàn)在沒(méi)有聯(lián)系。而u

21、sed to則著眼于過(guò)去和現(xiàn)在的對(duì)比，隱含現(xiàn)在已不存在，動(dòng)作或狀態(tài)都可表示。Would可以表示不規(guī)則的習(xí)慣，used to則不可。如： He used to be a naughty boy and cause trouble. I used to get up at six in the morning. Sometimes she would take a walk in the neighboring woods. In those days, whenever I had difficulties, I would go to Mr. Chen for help.六need和dare情

22、態(tài)動(dòng)詞用法例句need用于表示“需要，必要”之意。做情態(tài)動(dòng)詞時(shí)，僅用于否定句和疑問(wèn)句，只有現(xiàn)在時(shí)，過(guò)去式要用needn't have，疑問(wèn)式用need+人稱(chēng)?,否定式用need not(即needn't），1Need we leave soon? Yes, you must.(No, you needn't)2You needn't have hurried.(=It was not necessary for you to hurry，but you did).你當(dāng)時(shí)不必這么匆忙。做實(shí)義動(dòng)詞時(shí)，其變化與一般的實(shí)義動(dòng)詞相同，后接帶to的不定式（need doin

23、g = need to be done ）,過(guò)去式用needed、did you need?和didn't need,肯定式用needs/needed/need,疑問(wèn)式用do、does、did提問(wèn)，否定式要在前面加don't、doesn't、didn't1. A job like nursing needs patience and understanding.(need+名詞，need understanding=need to be understood,需要被理解)2He needs to see a doctor.(need to do)3Do you

24、still need volunteers to help clean up after the party?(need somebody to do something) 4They didn't need to start so early.(do not need to do)dare用于表示“敢于”之意。做情態(tài)動(dòng)詞，沒(méi)有人稱(chēng)和數(shù)的變化，主要用于否定句、疑問(wèn)句和條件狀語(yǔ)從句中1Dare you tell her the truth? Yes, I dare. /No, I darent.3 How dare you accuse me of lying!4 He darent a

25、dmit this.用作實(shí)義動(dòng)詞時(shí)，其變化與一般的實(shí)義動(dòng)詞相同。在肯定句中，dare后接帶to的不定式；否定句中，dare后既可接帶to的不定式，也可接不帶to的不定式。1 Only a few journalists dared to cover the story.2 He doesnt dare (to) go there alone.3 Dont you dare (to) touch it?七ought的用法：情態(tài)動(dòng)詞用法例句ought to do表示“應(yīng)該”之意1 You ought to take care of him.2 Ought I go now?Yes, you oug

26、ht to. /No, you oughtnt to.表示推測(cè)。注意與must表示推測(cè)是的區(qū)別1 He must be home by now. (斷定他已到家)2 He ought to be home by now. (不十分肯定)3 This is where the oil must be. (比較直率)4 This is where the oil ought to be. (比較含蓄)說(shuō)明：should與ought to 表示“應(yīng)該”時(shí)的區(qū)別should 表示自己的主觀看法，而ought to的語(yǔ)氣中，含有“按道理應(yīng)該”之意。若要反映客觀情況或涉及法律義務(wù)和規(guī)定，一般用ought

27、to。如： You should help them with their work. You are his father. You ought to get him to receive good education.八“情態(tài)動(dòng)詞+have done”用法情態(tài)動(dòng)詞+have done用法例句must have done 表示主觀上對(duì)過(guò)去已經(jīng)發(fā)生的行為進(jìn)行推測(cè)，意為“想必，準(zhǔn)是，一定做了某事”1 She must have gone through a lot.2 He must have visited the White House during his stay in the Unit

28、ed States.may/might have done表示對(duì)過(guò)去已發(fā)生行為的推測(cè)，意為“也許/或許已經(jīng)（沒(méi)有）“。一般用于肯定句或否定句中，不用于疑問(wèn)句。用might則表示語(yǔ)氣更加不肯定。1 You may have learnt the news.2 He may not have heard his name called.3 Sorry Im late. I might have turned off the alarm clock and gone back to sleep again.canhave donecannot have done表示對(duì)過(guò)去發(fā)生的行為的懷疑和不肯定，通

29、常用在否定句和疑問(wèn)句中。（can換成could時(shí)語(yǔ)氣委婉）1 Where can she have gone?2 Could he have done such a foolish thing?3 The boy cant have finished reading the book so soon because it is difficult even to an adult.could have done可用于肯定句中，表示“可能已經(jīng)”之意，此外，還可以表示過(guò)去能做而沒(méi)做的事，有一種對(duì)過(guò)去為付諸實(shí)施的事情的惋惜。1 He could have killed himself driving at a dangerous speed.2 You could have been more considerate.3 You could have done better, but you were too careless.might h