必修三unit1语法.ppt

1、Grammar,Modal verbs 情态动词 (I),Unit1 Festivals around the world,情态动词的语法特征,1）情态动词不能单独做谓语，除ought 和have外，后面只能接不带to的不定式。,2）情态动词没有人称，数的变化，但有些情态动词，如can、will也有一般式和过去式的变化。,3）情态动词的“时态”形式并不是时间区别的主要标志，不少情况下，情态动词的现在式形式和过去式形式都可用来表示现在时间、过去时间和将来时间。,can 1.表能力 “能够” cant “不能够” Eg. She can speak four foreign languages.

2、2.表许可或请求 Eg. You cant park your car in the street. Can you give me a hand? 3.表客观可能性 Man cannot live without air.,4.表怀疑、不肯定 can not have done sth. 不可能做了 Eg. He cannot have been to the town. Can he have got the book? 5.can have done 本来可以做而没做. Eg. He can have come earlier.,Could 1.用于表示泛指过去的能力 Eg. Icoul

3、dreadwhenIwasfour. 2.表请求（较委婉） Eg. Could you please give me a hand?,3.表示推测 could have done 本来能够做而没做 4.couldnt have done 不可能做了 Eg. She couldnt have done such a thing.,She can/is 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的主语是人或物,be able t

4、o的主语是人,Well be able to finish the work soon. I havent been able to see the film.,2.can只用于现在式和过去式(could) beableto可以用于各种时态,3.表示特定的某一过去能力或表示成功地做了某事时，只能用was/wereableto，不能用could,Hewasabletoflee（逃离）Europe before thewarbrokeout. Hewasabletoswimhalfway beforehegottired.,may和might,-May I use your pencil?,-Ye

5、s, you may./ No, you mustnt.,1. may和might 用于一般问句中表示委婉的请求,肯定回答用may,否定用mustnt,She may not be working now. John might be at home now.,2. may和might表示“可能性”, may/might + v 指现在或将来可能发生的动作情况。might暗示的可能性更小,She may/might have gone to the cinema. They may/might not have received our telephone.,3.对过去发生的事情的可能性作出判

6、断用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。,must 和haveto,1.Must用于一般问句中,肯定回答用must否定式用neednt或dont have to，做“不必”,mustnt表示“禁止，不允许”, MustIfinishallassignmentsatatime?,Yes, you must. No,youneednt.,Youmustntgetdownwhilethecarisstill moving.,I dont like this T

7、V set. We must buy a new one. There was no more bus. They had to walk home.,2.表示“必须”这个意思时，must和haveto稍有区别。must着重说明主观看法，haveto强调客观需要。 *时态方面,Youmustbethenewteacher. Hemustbejoking. Thereisnobodyhere.Theymusthaveall gonehome.,3.must表示对某人某事的猜测，用must have done,Will 和 would,If you will help me with my Eng

8、lish, I will be very happy. I promised that I would do my best.,1.will和would表示意愿、意志，可用于各种人称,Will you tell him the news as soon as he comes back？ Would you please speak again more slowly？,2.在疑问句中,will用于第二人称,表示请求或征求意见,would则语气更委婉,shall ,should 和ought to,You shall do as I say. (命令) Tell him that he sha

9、ll have the book tomorrow. (允诺) Nothing shall stop me doing it. (决心),1.shall用于第二、三人称表示允诺、警告、命令、决心等。,Shall I open the window for you？（征求意见） Shall he fetch some water for you？（请求）,2.在疑问句中,用于第一、三人称，用来表示请求或征求意见。,Young people should learn how to use computers. Every citizen ought to obey law. You ought n

10、ot to go.,3. should常表示劝告、建议、命令，与ought to意义相近，但ought to多表示责任、义务，语气强烈。在疑问句中通常用should代替ought to。,You should/ought to have told her the truth earlier. She shouldnt have left without saying a word.,4.should/ought to have done表示责备或批评,意为“本应该做到但没有做到”,用于否定则表示“本不该但”ought to的语气更强烈.,1.-There were already five p

11、eople in the car but they managed to take me as well. -It _a comfortable journey. ( ) A. cant be B. mustnt have been C. shouldnt be D. couldnt have been,D,2.The fire spread through the hotel very quickly but everyone _ get out. ( ) A. had to B. would C. could D. was able to,D,EXERCISES,4. Peter _ co

12、me with us tonight, but he isnt very sure. must B. can C. may D. will,C,5. - Could I call you by your first name? - Yes, you_. A. will B. could C. may D. might,C,6. Sorry, I m late. I _ have turned off the alarm clock and gone back to sleep again. might B. should C. can D. will,A,7.-Excuse me, but I

13、 want to use your computer to type a report. -You _ have my computer if you dont take care of it. A. shant B. might not C. neednt D. shouldnt,A,8. -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. need,B,9. With so much work on hand, you _to see the game last night. A. mustnt go B. could have gone C. shouldnt go D. shouldnt have gone,D,10.Johnny, you _play with the knife, you _hurt yourself. ( ) A. wont ; cant B. mustnt ; may C. shouldnt ; must D. cant ; wouldnt,B,11.There is n