摘要：e.g.—Can I borrow your book? —Yes, you can.
英语语法之中考复习与练习——表示许可、建议等的情态动词
一、表示许可:may/might和can/could
1.can /could表示允许，意为“可以”，could语气更委婉。
e.g.—Can I borrow your book? —Yes, you can.
—Could(不是can的过去式)I use your cell phone for a while?
—Yes, of course you can(表示允许别人做某事，用can，而不用could ).
2.may /might表示允许，意为“可以”，might语气更委婉。
e.g.You may use my ruler.
—May I Come in?
—Yes, you may(表示给予许可时，不用might ).
May/Might I have a few words with your manager, please，
He asked if he might use the phone.
3.may置于句首表示祝愿。
e.g.May you live long!
注：1.对于may引导的疑问句的回答有以下几种：
Yes，please./Yes, you may./No, you mustn't./No，you had better not./No，you can't.
二、表示请求、建议、命令、禁止、意志(意愿、决心)
1.must(必须)，mustn't(禁止)表示命令、禁止语气较强。
e.g.The children must be back by 4 o'clock.
You mustn't play football in the street. It's dangerous.
2.Can(Could) /Will(Would) you ...?表示提出请求、邀请、建议，一般用于疑问句，常用于第二人称。
e.g.Would you join us in the game?
Will you phone me later?
3.shall一般用于第一人称，表示征求对方的意见或请求对方。
e.g.What time shall I come?
Shall I change into the evening dress for your party?
4.will /would表示意愿、决心、愿望等。
e.g.---Can someone help me? ---I will.
We won't stay at your house for a long time.
He said he would fight for the world championship.
Would you like some cake?
5.dare“敢，有胆量”，多用于否定、疑问叹条件句中。
三、used to和can't help doing及had better
1.used to表示过去常常，否定式为usedn't to或didn't use to。
e.g.I used to take a walk every morning.
She used to live in Beijing.
He didn't use to be so careless.
2.had better(常略为'd better)意为“最好”，用于表示对别人的劝告、建议。
e.g.You had better be quiet.(用于现在)
You had better start tomorrow.(用于将来)
We had better be going out for a walk.(用于进行时)
You had better not miss the late bus.(否定语)
Hadn't you better ask him first？
3.can't help doing表示“不得不，禁不住”。
e.g.When I try to speak, I can't help making mistakes.
跟踪练习
1." I take it out?" "I'm sorry, you ."
A.Could ...couldn't B.Might...might not C.Could...can D.May...can't
2.He said that you watch TV all the evening if you wished.
A.may B.might C.can D.must
3.---Is John coming by train?
---He should, but he not. He likes driving his car.
A.must B.can C.may D.need
4.You park here! It's an emergency exit.
A.wouldn't B.mustn’t C.couldn't D.needn’t
5.Come on! We hurry because there isn't much time left.
A.must B.may C.can D.need
6.You go and see a doctor at once because you're got a bad fever.
A.can B.must C.dare D.would
7.The Yellow River flood large areas， but now the waters of it are used to energy.
A.was used to; producing B.used to; producing
C.was used to; produce D.used to; produce
8.A mobile phone of this type costs too much. You'd better .
A.wait B.waiting C.waited D.to wait
9.The Greens used to live in London and now they in Beijing.
A.used to live B.are used to live C.are used to living D.are used for living
10.There some flowers in the garden.
A.were used to be B.used to be C.uses to be D.used to be having
答案：DBCBA BDACB
来源：天哥教育
