情态动词表推测的用法

★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，但事实上却没有发生。
1）“could +have done sth” “本可能/本可以 做某事” couldn’t +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 didn’t see her in the meeting room this morning.She couldn’t have spoken at the meeting
must “命令”，“推测”
A，规定，指定
B，主观的命令，禁止
C，猜测，（语气肯定）
Should表劝告，建议，命令及合理推断
Can’t用于否定句
情态动词表示推测
1）might,may
表示主观的推测, Might------“也许” 否定 一般用于肯定句
May------“可能” 否定
might not may not
④---Cathrine,I have cleaned the room for you.
---Thanks.You
it.I could manage it myself.
A.needn’t to
B.needn’t have done
C.mustn’t do
D.shouldn’t have done
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
意志， 愿望，
决心
That bag looks heavy.I’ll help you with it. Thanks for lending me money.I’ll pay you back on Friday.
4.Accident can happen to any drunken driver.
可能性
5.It can’t be my father.He is now in England.
May &might
1.可能性
He may be very busy now.
He might be very busy now.
A.Should B.must C.wouldn’t D.can’t
③--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
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.
Eg：He might be right.他也许是对的。 He may not come tonight.他今晚可能不来
2）can
Can 用于主观推测时，常用于否定句（can’t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 can’t be at home,since I met him in the street just now.
Must&can’t
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.
⑤He paid for a seat,when he
have entered free.
A.Could B.would C.must D.need
⑥To enjoy the scenery ,Irene would rather spend long hours on the
train travl by air.
4）must
表主观的推测“一定”，语气十分肯定。其否定式为can’t“不可 能”，不用mustn’t，
mustn’t表示禁止，不允许，语气十分强硬。
Eg：He must be in the classroom now. You can’t have known the truth. Students mustn’t smoke.
情态动词表推测的用法
Can &could
表能力 1.My grandma is over eighty,but she can read without glasses.
表请求，许可 2.Can you wait a moment please?
3.Excuse me,coule you help me please?
This old man is strange.He will sit for hours
习惯
without saying anything.
We would sit around Grandpa after supper,listening
to his stories.
请求 （用于第二人称）
Will you come this way,please? Would you open the window?
3)need后接完成式主要用于否定句中。 “needn’t + have done ”表示本不必要做某事
Eg： You needn’t have watered the flowers,for it is going to rain.
①--Isn’t that Ann’s husband over there?
推测
He can’t be at home.I saw him in the classroom just now.
⑴Can &could
①表能力（ability）
⑵May&might
②表请求&允许（request &permission）
③可能性（possibility）
①表示可能性，might不是may的过去式；
A.As B.to
C.than
D.while
谢谢！
Shall &should
Shall we put off the sport meeting until next week?
请求
征求意见 Shall Tom go there with me tomorrow?
警告 允诺 威胁等
You shall if you don’t work harder. He shall have the book when in finish reading it.
2)“should/ought to +have done”本应该做，本应该发生 “should/ought to +have done”本应该做，本应该发生
Eg：I ought to have said it to her in a calmer mood. He shouldn’t have broken the red light.
No,it
be him----I’m sure he doesn’t wear glasses.
A.can’t B.must not C.won’t D.may not
②He
have completed his work;otherwise ,he wouldn’t be
enjoying himself by the seaside.
★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 can’t have done sth may not have done sth might not have done sth
Can用于肯定，理论上“可能” ② may表许可（permission）
③May用于祈使句，表祝愿
Can’t用于否定句中，主观猜测
⑶Will&would
①表意愿
②Will&would表习惯 ③表请求
⑷Shall和should
Shall的用法
征求意见（第一/三人称）
命令，警告等（第二/三人称）
Байду номын сангаас
⑸Must&can’t