一、 情态动词的用法（一） 情态动词的类型1、 只做情态动词的有：must、can（could）、may（might）2、 可做情态动词也可做实义动词的有：need3、 可做情态动词也可做助动词的有：will（would）、shall（should）4、 可做情态动词的某些特征的有：have to、ought to（二） 情态动词的特征1、 有一定的词义，但不能单独做谓语，必须和行为动词或系动词连用，构成谓语： must home（X） must go home（）2、 无人称和数的变化（have to）例外，用于第三人称单数时用has toWe must stay there. He must stay there.We have to walk home. He has to walk home.3、 后接动词原形：She may lose her way4、 具有助动词的作用，可用来构成否定句、疑问句及用于简明答语Can you sing an English song ? Yes, I can.（三） 情态动词的用法1、can、could的用法（1） 表示能力，译为：能，会。如：Can you play basketball? 你会打篮球么？（2） 表怀疑、猜测，常用于否定句和疑问句当中，如：He cant be in the room.他不可能在房间里。（3） 表请求或允许，多用于口语，意为“可以”，相当于may。如：You can(may) go now.你现在可以走了。（4） could是can的过去式，可以表示过去的能力。如：I could swim when I was seven years old.（5） 以can开头的一般疑问句，其肯定回答和否定回答分别用can和cant。2、may（过去式might）的用法（1）表推测，意为“可能，也许”，用于肯定句中。如：He may come tomorrow. 他明天可能会来。（2）表请求、许可，意为“可以“。如：May I borrow your book? 我可以借用你的书么？注意：may表请求，用于主语为第一人称的一般疑问句时，其否定回答用mustnt，不用may not，意为“不可以，不许，禁止“，如：May I go now? No, you mustnt不可以/ Yes, you may(can). 是，可以。 （3）表祝愿。如：May you succeed. 祝你成功 表示推测，意为一定，一般用于肯定句。在疑问句和否定句一般应用can，否定句也用may，但may not表示可能不，而cant表示不可能。如：Theres someone knocking on the door. 有人在敲门。It must be Jim. 肯定是吉姆。注意：在否定句中，mustnt表示禁止，意为不允许。以must开头的疑问句，肯定回答用must，而否定回答则常用neednt或者dont have to，意为不必，而不用mustnt。如：Must I finish the work today? 我今天必须完成工作么？No，you neednt/ you dont have to. 不，你不必（4）对need词性的判断：need后加to do说明need为实义动词，用助动词提问或否定；need后加doing表被动；若need后加动词原形，则need为情态动词，用need提问或否定，肯定回答用must，否定回答用neednt。如：You neednt come to school so early. 你不必这么早来学校。5、 had better的用法had better+动词原形，表示最好做某事，否定式用had better not do sth6、 shall（should）、will（would）的用法（1） shall用于第一人称，表示征求意见、询问。用于第二、三人称，表示命令如：Shall I open the window？ 我打开窗户好么？Shall we have lunch here？我们在这儿吃饭好么？You shall listen to the teacher in class. 课堂上你必须听讲。 （2） should常用来表示义务、责任。如：We should obey traffic laws. 我们应该遵守交通规则。（3） will用于第二人称表示询问、请求，也可以表达现在的意愿。如：Will you pass me the book? 你能把这本书递给我么？（4） would用来表示过去的意愿或委婉的询问。如：Would you tell me the way to the station？你能告诉我去东站的路么？7、 易混点清单（1） can和be able tocan和be able to表示能力时用法相同，can只用于现在时和过去式（could），但be able to表示经过努力后，能够做到有现在时，过去时和将来时。如：We will be able to come back next week.我们下周能回来。The fire spread through the hotel very quickly but everyone was able to get out.Jim couldnt speak Chinese last year, but now he can. Jim去年不会说中文但今年会。（2） can和may表示可能性的区别 在肯定句中用may表可能。如：You had better ask the policeman. He may know.你最好问问警察，他可能知道。 在否定句中，若语气肯定，表示不可能时用can not，若语气不肯定，表示可能不时用may not。Mr Li cant be in the room. He has gone to Beijing for a visit.李老师不可能在，他去北京度假了。（3） could，should，would，might表示委婉语气could，should，would，might等过去式有时不表示过去，而是表示更委婉客气的语气，如： Would you tell me the way to the park?你能告诉我去公园的路么？（4） maybe和may bemay为情态动词，后面跟动词原形be，用在句中。Maybe为副词，“大概，也许”，相当于perhaps，用于句首。（5） cant和mustnt表否定推测时应用cant，mustnt表达“禁止，不允许”的含义，不是用来表推测的，在肯定句中must表推测，意为“一定”。 Must I go to law school and be a lawyer like you, Dad? D No，you_, son. Youre free to make your own decision.A. cant B. mustnt C. shouldnt D. neednt Is Mr Brown driving here? AIm not sure. He_ come by train.A. may B. shall C. need D. must Look at the young lady in red. Is it Mrs King? DNo, it_ be her. She is wearing a white dress today.A. can B. may C. must D. cantB 1May I stop my car here? No, you_.A. cant B. mustnt C. neednt D. dont have toA 2. Must we clean the house now? No, you _.A. neednt B. may not C. mustnt D. cantC 3. John_ his father about his failure in the exam.A. dares not tell B. dares not telling C. dare not tell D. dares not to tellC 4. You_ return the book now. You can keep it next week if you like.A. cant B. mustnt C. neednt D. may notB 5. Johnny, you_ play with the knife, you_hurt yourself.A. wont.cant B. mustnt.may C. shouldnt, must D. cant.shouldntD 6. The fire spread through the hotel very quickly but everyone_ get out.A. had to B. would C. could D. was able toC 7. Would you go out for a walk with me? No, I _. My girl friend is coming.A. wouldnt B. shall not C. wont D. shouldntA 8. Man_ die without water.A. will B. can C. need D. shallD 9. If he started at 9 0clock, he_ be there by now.A. need B. shall C. ought to D. mustD 10. I mailed the letter two weeks ago. She _it.A. must receive B. cant receive C. might receive D. must have receivedA 11.The professor gave orders that the experiment _ before 5:30p.m.A. be finished B. will finish C. must be finished D. would be finishedD 12. There was plenty of time. You_.A. mustnt hurry B. mustnt have hurried C. neednt hurry D. neednt have hurriedA 13. Tom was a diligent(勤奋的) boy. He_ go to school though it was