Grammar and usage(1): Modal verbs: general introduction名师教学实录

情态动词和虚拟语气

I.

key points 1. can，be able to 和could

(1)can和be able to都表示能力，意思上没多大区别。但can只有现在和过去时，而be able to则有更多的形式。但当成功地完成某一具体动作时，通常不用could而用was/were able to来表示。这时was/were able to 相当于managed to，表示经过一番努力，终于能够完成某事。

Her mother can speak French.

The wounded man was still able to get to the village and was saved by the villagers in the end.

(2)表示猜测“可能”，一般用于疑问句和否定句。

—Can the news be true?

—It can’t be true.

Someone is knocking at the door. Who could it be? (3)can可以表示理论上的可能性，指常有的行为或情形，意为“有时会……”。

Anybody can make mistakes.

(4)表示请求、允许(表请求时，口语中常用could代替can使语气更委婉，回答时用can)。

Can I go now?

—Could I come to see you tomorrow?

—Yes，you can. (否定答语可用No，I’m afraid not. ) (5)表示惊异、怀疑、不相信的态度(主要用于否定句、疑问句或感叹句中)。

How can that be true？I can’t believe my eyes and ears.

How could you be so careless?

(6)can的特殊用法。

can but只有；can’t but不得不；can’t. . . too再……也不为过，越……越好

I can but wait.

I can’t but wait.

You can’t be too patient to the customers.

题组训练1

用can，could，be able to的适当形式填空

1. Though the building was on fire，they

go out safely.

2. It

be the postman at the door.

It’s only six o’clock.

3. —How’s your new babysitter?

—We

not ask for a better one.

All our kids love her so much.

4. The police still haven’t found the lost child，but they’re doing all they

.

5. You

be too careful when driving.

2. may和might的用法

(1)表示允许、请求，might比may的语言更委婉一些。

—May I watch TV now?

—Yes，you may. (Yes，please. )

—No，you mustn’t. (No，you’d better not. )

(2)表示可能性时，might比may的可能性小，may表示的可能性比can小(主要用于陈述句、肯定或否定句，疑问句用can代替)。

The story may not be true.

(3)表示祝愿(不用might)

May you succeed!

(4)may/might as well最好还是……，不妨

You might as well do it now.

(5)may/might well很可能

He may well be late for class.

题组训练2

用may，might的适当形式填空

1. —I don’t really like James.

Why did you invite him?

—Don’t worry.

He

not come.

He said he wasn’t certain what his plans were.

2. —I left my handbag on the train，but luckily someone gave it to a railway official.

—How unbelievable to get it back! I mean，someone

have stolen it.

3. As a student，you

as well make good use of your time.

4. You

go to school either by bike or by bus.

5.

she rest in peace.

3. must，have to和ought to的用法

(1)must表示“必须，应该，一定要”。强调主观看法，只有现在时形式，否定式是must not(mustn’t)。must开头的问句，其否定回答要用needn’t或don’t have to代替。

(2)must表示必然的结果。

All men must die.

(3)must还可表示主语固执、偏要做他人不希望做的事。

It can’t help；he must do that.

(4)have to着重客观需要，能用于更多时态(过去时或将来时)。

He will have to be there before ten.

②dare作实义动词时，在肯定句中要接to，在疑问句和否定句中to可省去。

He dares to catch a snake.

I do not dare (to) complain.

Do you dare (to) swim in the river?

题组训练3

同义句改写

1. He daren’t go out at night.

He

go out at night.

2. The flowers need watering.

The flowers need

.

5. will和would的用法

(1)will

①表示请求、建议，常用于第二人称。

Will you please go with me?

②表示意愿、决定、允许。

I will never do that again.

③表示习惯性动作或某种倾向，“总是，惯于”，通常用于第三人称。

Rosa will always be late for school.

(2)would

①表示请求、建议，比will委婉，指现在时间，多用于第二人称。

Would you like a cup of tea?

②表示过去习惯性动作或某种倾向。

We would play badminton on Sundays.

6. shall和should的用法

(1)shall

用于第一、三人称，在问句中表示征求对方意见或请求。

Shall I come in? 用于第二、三人称的陈述句中，表示命令或威胁。

You shall do as your father says.

(2)should

①表示责任、义务，意为“应该”。

②表示惊讶语气，意为“竟然”。

You should wear slippers in class.

③用于条件句，表示“假如，万一”，省去if，should可提至句首。

Should you be late，apologize to the teacher.

7. 情态动词表示推测或判断的用法

情态动词

对现在和未来的推测

must

must＋do

对过去的推测

must have done

may/might done

have 使用场合

肯定句

肯定句、否定句

may/might may/might＋do

can/could

can/could do

should

can/could have done

否定句、疑问句(could可用于肯定句)

肯定句、否定句、疑问句

用来表示一种估计的

情况“按理会/估计会”

should have done

should do

情态动词＋have done的用法：

(1)should have done表示“本来应该做某事而实际上未做”，而shouldn’t have done则表示“本不应该做某事而实际上做了”。

You should have told me about it earlier.

You shouldn’t have said such words to your parents.

(2)ought to have done也表示“本应该……”，而ought not to have done则意为“本不应该……”。

You ought to have told me about it earlier.

You ought not to have said such words to your parents.

(3)needn’t have done表示“本无必要做某事而实际上做了”。

You needn’t have walked so quickly since time was enough.

(4)could have done表示“本来有可能……而事实上未做到”。

I could have come on time，but my car broke down on the way.

(5)may/might have done表示“过去可能发生过某事”或“本来应该或可以做某事(实际上没做)”。

You might have given him more help，but you were so busy.

题组训练4

1. I

(我本来可以帮助你的)，but I was too busy then.

2. It’s Sunday.

He

(不可能上学去了).

3. You know the story very well.

You

(可能读过) before.

4. You

(一定是睡得很晚) last night.

Your eyes are red.

5. I

(本应该做作业) last night，but I went to the cinema.

◆虚拟语气的核心考点

1. 虚拟语气用于条件状语从句

(1)表示与现在事实相反的假设，条件状语从句中的谓语动词用一般过去时(be动词用were)，而主句中的谓语动词用“would/should/could/might＋动词原形”。

If I were you，I would buy that house.

If he had time，he should go with you.

(2)表示与过去的事实相反，条件状语从句中的谓语动词用过去完成时，主句中的谓语动词则用“would/should/might/could＋have＋过去分词”。

If he had taken my advice，he would have succeeded in passing the examination.

(3)表示与将来事实相反，条件状语从句中的谓语动词用一般过去时或“should/were to＋动词原形”，而主句中的谓语动词则用“would/should/could/might＋动词原形”。

If it were to rain tomorrow，the football match would be put off.

(4)当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间作相应调整。

If they had worked hard，they would be very tired now. (从句说的是过去，主句指的是现在)

题组训练5

用所给动词的正确形式填空

1. Maybe if I

(study) science，and not literature then，I would be able to give you more help.

2. If I

(have) time next week，I would go to the party.

3. If I

(be) you，I should go and see the dentist at once.

4. If you had arrived at the station ten minutes earlier，you

(catch) the train.

5. If he were you，he

(miss) the concert last night.

2. 虚拟语气用于名词性从句

(1)虚拟语气在宾语从句中的运用。

①“wish＋宾语从句”表示不能实现的愿望，译为“要是……就好了”等。表示现在不能实现的愿望，从句中的谓语动词用一般过去时；表示将来不能实现的愿望，从句中的谓语动词用“would/could＋动词原形”；表示过去不能实现的愿望，从句中的谓语动词用“had＋过去分词”或“could/should＋have＋过去分词”。

I wish it were spring all the year round.

I wish I had known the answer.

I wish I could fly like a bird.

②在表示建议、要求、命令等动词后的宾语从句中，谓语动词用“should＋动词原形”，should可以省略。

常见的动词有：suggest，advise，propose，demand，require，insist，request，command，order等。

She suggested we (should) leave here at once.

The doctor ordered she should be operated on.

(2)虚拟语气在同位语从句和表语从句中的运用。

表示建议、要求、命令等的名词，如advice，idea，order，demand，plan，proposal，suggestion，request等，其后的表语从句和同位语从句中谓语动词用“(should＋) 动词原形”，should可以省略。

His suggestion that we (should) go to Shanghai is wonderful.

My idea is that they (should) pay 100 dollars.

(3)虚拟语气在主语从句中的运用。

在主语从句中，谓语动词的虚拟语气用“(should＋)动词原形”的结构，表示惊奇、不相信、理应如此等。

It is necessary (important，natural，strange，etc. )that we (should) clean the room every day.

It was a pity (a shame，no wonder，etc. )that you (should) be so careless.

It will be desired (suggested，decided，ordered，requested，proposed，etc. )that she (should) finish her homework this afternoon.

注意：这种从句表示的是事实。如果人对这种事实表现出惊奇的情感，就可用虚拟语气；反之，如果不表示惊奇等情感，that从句也可用陈述句语气。

It is a pity that you can’t swim.

题组训练6

用所给词的适当形式填空

1. —Where are the children？The dinner’s going to be completely ruined.

—I wish they

(be，not) always late.

2. It is requested that Class Two

(give) a performance at the English evening.

3. He insisted that a deadline

(set) for completing the task.

4. My suggestion is that we

(go) without delay.

5. The doctor has given advice that the patient

(give) up smoking.

3. 虚拟语气在其他场合的运用

(1)虚拟语气在as if/as though，even if/even though等引导的表语从句或状语从句中，如果从句表示的动作发生在过去，用过去完成时；指现在状况，则用一般过去时；指将来状况则用过去将来时。

He did it as if he were an expert.

Even if she were here，she could not solve the problem.

(2)虚拟语气用于定语从句中。

这种从句常用于句型“It is (high)time (that). . . ”中，定语从句的谓语动词用一般过去时(be用were)或“should＋动词原形”，意思是“(现在)该……”。

It’s time that I picked up my daughter.

It’s high time we went/should go home

(3)虚拟语气用在if only引导的感叹句中。

If only I were a pilot.

If only I had taken his advice.

(4)虚拟语气在一些简单句中的运用。

①情态动词的过去式用于现在时态时，表示说话人谦虚、客气、有礼貌或语气委婉，常出现在日常会话中。

It would be better for you not to stay up too late.

Would you be kind enough to close the door?

②用于一些习惯表达法中。

Would you like a cup of tea?

I would rather not tell you.

II.

Consolidation感悟高考

1. Had the governments and scientists not worked together，AIDS-related deaths

since their highest in 2005. (2016·浙江，15)

A. had not fallen

B.

would not fall

C.

did not fall

D. would not have fallen

2. Why didn’t you tell me about your trouble last week? If you

me，I could have helped. (2016·北京，34)

A. told

B. had told

C. were to tell

D. would tell

3. It might have saved me some trouble

the schedule. (2015·江苏，28)

A. did I know

B. have I known

C. do I know

D. had I known

4. If I

it with my own eyes, I wouldn’t have believed it. (2015·北京，34)

A. didn’t see

B. weren’t seeing

C. wouldn’t see

D. hadn’t seen

5. I wish I

at my sister’s wedding last Tuesday，but I was on a business trip in New York then. (2015·天津，13)

A.

will be

B.

would be

C.

have been

D.

had been

6. It is lucky we booked a room，or we

nowhere to stay now. (2015·安徽，32)

A. had

B. had had

C. would have

D. would have had

7. Ellen is a fantastic dancer. I wish I

as well as her. (2015·陕西，23)

A. dance

B. will dance

C. had danced

D. danced

8. We

back in the hotel now if you didn’t lose the map. (2014·北京，34)

A. are

B. were

C. will be

D. would be

9. If we

a table earlier，we wouldn’t be standing here in a queue. (2013，北京，34)

A. have booked

B. booked

C. book

D. had booked

10. —Do you think George has passed the driving test?

—No. If so，he

his car to our college yesterday. (2013·福建，30)

A. would drive

B. drove

C. would have driven

D. had driven

11. I should not have laughed if I

you were serious. (2013·江苏，30)

A. thought

B. would think

C. had thought

D. have thought

12. If he had spent more time practising speaking English before，he

able to speak it much better now. (2013·天津，14)

A. will be

B. would be

C. has been

D. would have been

13. —It rained cats and dogs this morning. I’m glad we took an umbrella.

—Yeah，we would have got wet all over if we

. (2013·重庆，29)

A. hadn’t

B. haven’t

C. didn’t

D. don’t

14. I

to my cousin’s birthday party last night，but I was not available. (2013·安徽，28)

A. went

B. had gone

C. would go

D. would have gone

15. My mom suggests that we

eat out for a change this weekend. (2013·陕西，12)

A. should

B. might

C. could

D. would