情态动词表推测的用法

1、 1.My grandma is over eighty,but she can read without glasses.2.Can you wait a moment please? 3.Excuse me,coule you help me please? 4.Accident can happen to any drunken driver. 5.It cant be my father.He is now in England.表能力表请求，许可可能性Can &couldMay &might1.可能性He may be very busy now.He might b

2、e very busy now.May表许可- He may go now. May I go now?祈使句- May you succeed! May you have a nice trip!Will &would That bag looks heavy.Ill help you with it. Thanks for lending me money.Ill pay you back on Friday.This old man is strange.He will sit for hours without saying anything. We would sit aro

3、und Grandpa after supper,listening to his stories.Will you come this way,please?Would you open the window?意志，愿望，决心习惯请求（用于第二人称）Shall &should Shall we put off the sport meeting until next week?Shall Tom go there with me tomorrow?You shall if you dont work harder. He shall have the book when in fin

4、ish reading it.请求征求意见警告允诺威胁等Must&cant规定、指令 You must have a passport if you want to go abord.主观的命令、禁止 You can go out with your friend but you must come back before 11 at night.You must be ill.I can see it from your face. He cant be at home.I saw him in the classroom just now.推测Can &could 表能力（

5、ability）表请求&允许（request &permission）可能性可能性（possibility）Can用于肯定，理论上“可能”Cant用于否定句中，主观猜测May&might表示可能性，might不是may的过去式； may表许可（permission）May用于祈使句，表祝愿Will&would表意愿Will&would表习惯表请求Shall和和shouldShall的用法征求意见（第一/三人称）命令，警告等（第二/三人称）Must&cantmust“命令”，“推测”A，规定，指定B，主观的命令，禁止C，猜测，（语气肯定）Cant用

6、于否定句Should表劝告，建议，命令及合理推断情态动词表示推测1）might,may Might-“也许” May-“可能”Eg：He might be right.他也许是对的。 He may not come tonight.他今晚可能不来否定might not 否定may not表示主观的推测,一般用于肯定句2）can Can 用于主观推测时，常用于否定句（cant不可能）和疑问句， 疑问句中也可以用could Can用于肯定句时，表示一时的，客观的可能性。Eg:-Can he be at home now? 他现在在家吗？ -No,he cant be at home,since I

7、 met him in the street just now. 不，他不可能在家，因为我刚才才大街上遇到他了。 Could she be chatting on the internet? 她现在可能在网上聊天吗？ 3)Should 和和ought to 表示根据常规、事理、经验做出的判断，“想必”“应该”。Eg：Today is Sunday. Our teacher should be at home. That ought to be enough food for the four of us.4）must表主观的推测“一定”，语气十分肯定。其否定式为cant“不可能”，不用must

8、nt， mustnt表示禁止，不允许，语气十分强硬。Eg：He must be in the classroom now. You cant have known the truth. Students mustnt smoke.一些情态动词后接完成式是对过去情况的肯定或否定的推测或推断。 must have done sth may have done sth might have done sth cant have done sth may not have done sth might not have done sth还有一些情态动词后接完成式表示动作按理应在过去发生，但事实上却没有

9、发生。1）“could +have done sth” “本可能/本可以 做某事”couldnt +have done sth “本不可能/本不可以 做某事”Eg ：He thought a ticket when he could have entered free. I didnt see her in the meeting room this morning.She couldnt have spoken at the meeting2)“should/ought to +have done”本应该做，本应该发生 “should/ought to +have done”本应该做，本应该

10、发生Eg：I ought to have said it to her in a calmer mood. He shouldnt have broken the red light.3)need后接完成式主要用于否定句中。 “neednt + have done ”表示本不必要做某事Eg： You neednt have watered the flowers,for it is going to rain.-Isnt that Anns husband over there?No,it be him-Im sure he doesnt wear glasses.A.cant B.must

11、not C.wont D.may notHe have completed his work;otherwise ,he wouldnt be enjoying himself by the seaside.A.Should B.must C.wouldnt D.cant-Excuse me.Is that the right way to the Summer Palace?-Sorry,I am not sure.But it be.A.Might B.will C.must D.can-Cathrine,I have cleaned the room for you.-Thanks.Yo

12、u it.I could manage it myself. A.neednt to B.neednt have done C.mustnt do D.shouldnt have doneHe paid for a seat,when he have entered free.A.Could B.would C.must D.needTo enjoy the scenery ,Irene would rather spend long hours on the train travl by air.A.As B.to C.than D.while-Lucy doesnt mind lending you her dictionary.-She . Ive already borrowed one.A.cant B.mustnt C.neednt D.shouldnt-Who is the girl standing over there?-Well ,if you k