1、2021/8/11 星期三1GrammarModal verbs 情態(tài)動(dòng)詞 (I)Unit1 Festivals around the world2021/8/11 星期三2情態(tài)動(dòng)詞的語(yǔ)法特征1）情態(tài)動(dòng)詞不能單獨(dú)做謂語(yǔ)，除ought 和have外，后面只能接不帶to的不定式。 2）情態(tài)動(dòng)詞沒(méi)有人稱(chēng)，數(shù)的變化，但有些情態(tài)動(dòng)詞，如can、will也有一般式和過(guò)去式的變化。3）情態(tài)動(dòng)詞的“時(shí)態(tài)”形式并不是時(shí)間區(qū)別的主要標(biāo)志，不少情況下，情態(tài)動(dòng)詞的現(xiàn)在式形式和過(guò)去式形式都可用來(lái)表示現(xiàn)在時(shí)間、過(guò)去時(shí)間和將來(lái)時(shí)間。2021/8/11 星期三3can, could 和be able to的用法She can

2、/be able to sing the song in English.This machine can make you feel comfortable.1.can, be able to都可表示“能力”Can的主語(yǔ)是人或物,be able to的主語(yǔ)是人 Well be able to finish the work soon.I havent been able to see the film.2.can只用于現(xiàn)在式和過(guò)去式(could)。beableto可以用于各種時(shí)態(tài)。 could用于表示泛指過(guò)去的能力。如： IcouldreadwhenIwasfour. 2021/8/11 星

3、期三4Although the soldier was badly wounded, he was able to tell what had happened.She ran fast but she couldnt /wasnt able to catch the bus.3.表示特定的某一過(guò)去能力或表示成功地做了某事時(shí)，只能用was/wereableto，不能用could。 HewasabletofleeEuropebeforethewarbrokeout. Hewasabletoswimhalfwaybeforehegottired. 表示過(guò)去的能力2021/8/11 星期三5Coul

4、d I have a look at your notebook?Yes , you can./No,youcant. 4.could不表示時(shí)態(tài) ,表示委婉的請(qǐng)求，（注意在回答中不可用could）。 Can this news be true?How can you be so foolish? It cant be Mary. She has fallen ill.5.表示“驚異,懷疑,不相信”的態(tài)度(主要用于否定句,疑問(wèn)句和感嘆句中)2021/8/11 星期三6Linda didnt catch the train. She could have caught it. Dontworry.

5、 Theycouldhavejustforgottentophone. 6.表示推測(cè)，譯為“可能、或許”，can常用于否定句(意思是不可能已經(jīng))和疑問(wèn)句；could除用于否定句及疑問(wèn)句外,還可用于肯定句(意思是那時(shí)可能;本來(lái)可以)。2021/8/11 星期三7may和might -May I use your pencil?-Yes, you may./ No, you mustnt.1. may和might 用于一般問(wèn)句中表示委婉的請(qǐng)求,肯定回答用may,否定用mustntShe may not be working now. John might be at home now.2. may

6、和might表示“可能性”, may/might + v 指現(xiàn)在或?qū)?lái)可能發(fā)生的動(dòng)作情況。might暗示的可能性更小 2021/8/11 星期三8She may/might have gone to the cinema. They may/might not have received our telephone.3.對(duì)過(guò)去發(fā)生的事情的可能性作出判斷用may/might have done,用might比用may的可能性更小 May you succeed! MayGodblessyou! 4.may放在句首祈使句，表示祝愿。 2021/8/11 星期三9Will 和 wouldIf you

7、 will help me with my English, I will be very happy. I promised that I would do my best.1.will和would表示意愿、意志，可用于各種人稱(chēng)Will you tell him the news as soon as he comes back？ Would you please speak again more slowly？2.在疑問(wèn)句中,will用于第二人稱(chēng),表示請(qǐng)求或征求意見(jiàn),would則語(yǔ)氣更委婉2021/8/11 星期三10shall ,should 和ought toYou shall do

8、as I say. (命令) Tell him that he shall have the book tomorrow. (允諾) Nothing shall stop me doing it. (決心) 1.shall用于第二、三人稱(chēng)表示允諾、警告、命令、決心等。Shall I open the window for you？（征求意見(jiàn)） Shall he fetch some water for you？（請(qǐng)求）2.在疑問(wèn)句中,用于第一、三人稱(chēng)，用來(lái)表示請(qǐng)求或征求意見(jiàn)。2021/8/11 星期三11Young people should learn how to use computer

9、s. Every citizen ought to obey law. You ought not to go.3. should常表示勸告、建議、命令，與ought to意義相近，但ought to多表示責(zé)任、義務(wù)，語(yǔ)氣強(qiáng)烈。在疑問(wèn)句中通常用should代替ought to。2021/8/11 星期三12You should/ought to have told her the truth earlier. She shouldnt have left without saying a word.4.should/ought to have done表示責(zé)備或批評(píng),意為“本應(yīng)該做到但沒(méi)有做到

10、”,用于否定則表示“本不該但”ought to的語(yǔ)氣更強(qiáng)烈.2021/8/11 星期三13must 和haveto1.Must用于一般問(wèn)句中,肯定回答用must否定式用neednt或dont have to，做“不必”,mustnt表示“禁止，不允許” MustIfinishallassignmentsatatime? Yes, you must. No,youneednt. Youmustntgetdownwhilethecarisstill moving. 2021/8/11 星期三14I dont like this TV set. We must buy a new one. Ther

11、e was no more bus. They had to walk home.2.表示“必須”這個(gè)意思時(shí)，must和haveto稍有區(qū)別。must著重說(shuō)明主觀看法，haveto強(qiáng)調(diào)客觀需要。另外，haveto能用于更多時(shí)態(tài)。 2021/8/11 星期三15Youmustbethenewteacher. Hemustbejoking. Thereisnobodyhere.Theymusthaveall gonehome. 3.must表示對(duì)某人某事的猜測(cè)，作“準(zhǔn)是”，“一定” ，一般用于肯定句中。對(duì)過(guò)去發(fā)生的事情作肯定判斷用must have done He must come and wo

12、rry her with question, just when she was busy cooking the dinner. Of course，after I gave her my advice，she must go and do the opposite。4. Must表示“偏要，硬要”，指做令人不快的事情2021/8/11 星期三161.-There were already five people in the car but they managed to take me as well. -It _a comfortable journey. ( ) A. cant be

13、 B. mustnt have been C. shouldnt be D. couldnt have beenD2.The fire spread through the hotel very quickly but everyone _ get out. ( ) A. had to B. would C. could D. was able toDEXERCISES2021/8/11 星期三174. Peter _ come with us tonight, but he isnt very sure. must B. can C. may D. willC5. - Could I cal

14、l you by your first name? - Yes, you_. A. will B. could C. may D. mightC6. Sorry, I m late. I _ have turned off the alarm clock and gone back to sleep again. might B. should C. can D. willA2021/8/11 星期三187.-Excuse me, but I want to use your computer to type a report.-You _ have my computer if you do

15、nt take care of it.A. shant B. might not C. neednt D. shouldntA8. -When can I come for the photos ? I need them tomorrow afternoon. -They _be ready by 12 : 00 . A. can B. should C. might D. needB9. With so much work on hand, you _to see the game last night. A. mustnt go B. could have goneC. shouldnt go D. shouldnt have goneD2021/8/11 星期三1910.Johnny, you _play with the knife, you _hurt yourself. ( )A. wont ; cant B. mustnt ; mayC. shouldnt ; must D. cant ; wouldntB11.There i