情态动词的精讲与专项练习

情态动词的精讲与专项练习
情态动词（M o d a l V e r b s）情态动词本⾝有⼀定的词义，表⽰说话⼈对动作的观点，如需要、可能、意愿或怀疑等语⽓或情态。

它不能单独作谓语，只能和实义动词（⾏为动词）⼀起构成谓语。

情态动词没有⼈称和数的变化。

常⽤的情态动词有：can、could、may、might、must、have to（had to）、ought to、need、dare. 此外shall、should、will、would在⼀定场合下也可⽤作情态动词。

c a n/c o u l d
情态动词can/could有下列⼏种形式
注：美国英语中往往⽤can not 替代cannot.
⼀、表⽰能⼒
can/could都可以表⽰能⼒，“能够、能、会”，包括本能、体能、智能、技能等。

could 表⽰过去的能⼒情况；can 表⽰现在断定将来能够或询问将来是否能够；表⽰将来的能⼒是⼀般⽤will be able to.
Is there anything else I can do for you? 我还能为你做些别的事吗？
I can manage it myself. 我⾃⼰可以设法处理此事。

Can you come to my party tomorrow evening? 明天晚上你能来参加晚会吗？
The theatre can seat 3,000 people. 这戏院可坐3，000⼈。

Doing this can save a lot of time and money. 这样做可以节省许多时间和⾦钱。

Before liberation, few workers could support their families. 解放前，很少⼯⼈能养家。

Mozart could play the piano at the age of 3. 莫扎特在三岁时就会弹钢琴。

I can easily tell my father’s step. 我能轻松地判别出我⽗亲的脚步声。

My grandma is over eighty, but she can read without glasses. 我奶奶已过⼋旬，但她读书仍不需要眼镜。

The child will be able to walk well in another month. 再过⼀个⽉这个⼩孩就能⾛得很好了。

⼆、表⽰推测
1、can常在肯定句中表⽰客观可能性。

有时表⽰⼀时的可能性，常译作“有时候会”。

Driving on these snowy roads can be very dangerous. 在这些多雪的路上开车有时会很危险。

Accidents can happen to any drunken driver. 喝醉酒的司机都有可能发⽣交通事故。

Jeff is a very clever boy, but he can be very dull sometimes. Jeff是个聪明的孩⼦，但有时也会有点⼉迟钝。

China can be very hot in summer. 中国的夏天有时会很热。

In winter in North China, the temperature can be below -40°C. 冬天在华北，温度有时候会低于-40°C.
2、can/could ⽤在否定句或疑问句中，表⽰怀疑、惊讶、不相信之意。

这时can与could没有时间上的差别，只是could语⽓较缓和。

⽤于否定句时，意为“不可能”。

What can/could he be doing at this time of night？都到夜晚这个时候了，他究竟在⼲什么呢？
How can/could you believe such a liar like him? 你怎么能相信像他那样的⼀个骗⼦呢？
She can’t/couldn’t be serious about it. 她不可能认真对待这件事。

It can’t be true, Pierre!. ⽪埃尔，这不可能是真的。

[摘⾃《⾼⼀教材下册》P6}
I believe him. He can’t/couldn’t be such an irresponsible man.我信任他。

他应该不是⼀个如此不负责任的⼈。

Can this be an excuse for not giving them help? 这难道能成为不帮助他们的理由吗？
How can you so careless! 你怎么能这么粗⼼呢！
What can they mean by saying that? 他们说这话可能是什么意思呢？
3、can have done 表⽰从现在猜测过去。

can have done 主要⽤于否定句或疑问句中。

在肯定句中表⽰对过去的可能性推测时，
不⽤can have done，⽽⽤must have done.
Where can Mary have gone？She can’t have gone to school. It is Sunday. 玛丽究竟到哪⾥去了？她不可能上学去，今天是星期天。

Can the bank have made a mistake? It was not possible, I suppose. 银⾏有没有可能出错呢？我想是不可能的。

Tree after tree went down, cut down by the water, which must have been three meters deep.
树⽊⼀棵⼀棵倒下，是被⽔冲断的，当时⽔肯定有3⽶深。

[摘⾃《⾼⼀英语教材P25》]
三、表⽰许可can/could 可是⽤来表⽰“向对⽅请求许可”、“给予对⽅许可”、“陈述许可”等。

1、向对⽅请求许可。

在不拘礼节时常⽤can，需要讲究礼貌时⽤could。

常见的句型有Can I …? Could I …? 肯定回答时常
⽤Sure/Of course/Certainly/Yes, of course. 否定回答时常⽤No, of course not./ No, you can’t 礼貌回答时常⽤Sorry，I’m afraid you can’t.
Can I have a look at your new design? 我可以看⼀下你的新设计吗？
--- Could I use your phone? --- 我可以⽤⼀下你的电话吗？
--- Yes， of course you can. --- 当然可以。

★[特别注意]在回答Can I …? Could I …?的答语中不能⽤could；
Can I 也可⽤May I 替代（更礼貌），Might I 很少⽤。

Could I take this seat, sir, if you don’t mind? 先⽣，如果你不介意，我可坐这个位⼦吗？
--- Could I borrow your bike for afternoon? 我可以借你的⾃⾏车⽤⼀下午吗？
--- Yes, you can. / No, you can’t.
2、给予对⽅许可。

当表⽰允许别⼈做什么事时，可⽤can也可⽤may，但不⽤could。

表⽰“不允许”时，⽤cannot、can’t. You can have a short holiday after this item of work. 做完这项⼯作后，你可以修⼀个短假。

You can’t smoke or crack sunflowers seeds in the theatre. 在剧院中你不能抽烟或吃⽠⼦。

--- Could I use your cell phone for a while? 我可以⽤⼀会⼉你的⼿机吗？
--- Yes, of course, you can. 好的，当然可以。

That’s all for today. You can leave now. 今天就这些，你现在可以⾛了。

The class is over. You can go home now. 下课了，你们可以回家了。

四、表⽰征求对⽅意见
在征求对⽅意见时常⽤Could/Can you…？此时也可⽤Would/Will you …? 不过Could/Would you…？⽐更有礼貌。

Could you please help me with this furniture? 你可以帮我办⼀下这件家具吗？
Could you pick me up at the airport at 5 next Monday? 下周⼀五点你能到机场接我吗？
Can you help me with the housework? 你能帮我做家务吗？
五、c a n/c o u l d的固定习惯⽤法
1、can’t but作“只好”讲，是正式⽤法，⼀般场合下常⽤can only.
We can’t but do our best. 我们只好尽⼒⽽为。

We couldn’t but stay until help come. 我们只好等着有⼈来帮忙。

I can’t but ask him about it. 关于这件事我只好问他。

2、cannot help but作“不得不、不能避免”讲，后加动词原形。

I can’t help but often think of my parents. 我常常禁不住想起我的⽗母。

The girl couldn’t help but live on herself. ⼩⼥孩不得不⾃⾷其⼒。

3、can’t help作“不禁”讲，后⾯加名词、代词、doing或one’s doing.
When I try to speak, I can’t help making mistakes. 我⼀开⼝说话，就禁不住犯错误。

I can’t help children/children’s being rude to me. 我不能容忍孩⼦们对我的粗鲁⽆礼。

六、c o u l d在虚拟语⽓中构成谓语。

could在虚拟语⽓中常与动词的完成式连⽤，表⽰过去本可以完成⽽实际上却未完成的动作。

If you had come to the party yesterday, you could have met Mr. Lesley.
If you studied harder, you could have got much better grades. 要使你更加⽤功的话，你本可以取得更好的成绩。

If you had been a little more careful, you could have avoided this serious mistake.假如你稍加注意的话，你本可以避免这种严重的错误。

七、特别提⽰cannot…too…表⽰“⽆论怎样……都不过分”、“越…越好”。

有时cannot可以⽤can never代替。

We can’t thank you too much for what you’ve done for us. 对于你对我们所做的⼀切，我们怎么感激你都不过分。

You cannot be too careful to cross the road. 过马路时怎么⼩⼼都不为过。

You can never do the work too well. 这项⼯作你做得越出⾊越好。

m a y/m i g h t
⼀、表⽰允许，其意为“可以”。

1、表⽰请求允许，即请求别⼈允许⾃⼰做某事，may、might都可以⽤，只是might表⽰的语⽓较委婉，但并不表⽰过去。

May I come in？我可以进来吗？
Might/may I take this book home? 我可以把书带回家吗？
I wonder if I might use your umbrella. 不知道我是否可以⽤你的伞。

May I trouble you to pass me the book? 能不能⿇烦你把那本书递给我？
Might I take the liberty of pointing out your mistakes? 我可不可以冒昧指出你的错误？
--- May I borrow your bicycle? --- Certainly.
Students may not stay out after 10:30 p.m. without written permission.没有书⾯同意，学⽣晚上10：30后不得留在外⾯。

2、表⽰给予允许，即⾃⼰允许别⼈做某事，通常⽤may⽽不⽤might. might ⼀般不表⽰过去，但是在间接引语中可做may的过去式，转述已经给予的允许。

You may take this seat if you like. 如果你⾼兴可以坐在这⾥。

--- May/Might I go out and play basketball? --- 我现在可以出去打篮球吗？
--- Yes, you may/can. (Yes, please) [由于答语是表⽰给予允许，可⽤may，但不能⽤might]
--- May I smoke here?
--- Yes, please. (或Yes, you can.) / No, please don’t. (或No, you mustn’t)
He said that I might use his telephone. 他说我可以⽤⼀下他的电话。

He asked if he might glance through my album. 他问可不可以翻翻我的相册。

Father said that I might play basketball before supper. 爸爸说我可以在晚饭前踢⾜球。

★[特别注意]在对may表⽰“请求许可”的问句的回答时，即在回答May/Might I …？问句时，
作肯定回答可以⽤“Yes，you may.”(过于严肃正式⽽不常⽤)
或“Yes, please.”（请便。

更⼝语化）
或“Of course. / Certainly” (当然可以)
作否定回答时常⽤“No，you mustn’t. “(表⽰禁⽌)不⾏，
或“Please don’t”请不要，注意作否定回答时不⽤”No，you mat not.”
⼆、表⽰推测，意为“可能”。

might⽐may语⽓更不确定，表⽰可能性更⼩。

两者都可⽤于肯定句或疑问句，但⽤于疑问句时，may通常不⽤于句⾸，⽽might 有时可⽤于疑问句的句⾸。

You may/ might be wrong. 你可能是错的。

He might be an Englishman. 他也许是个英国⼈。

He may/might be sleeping now. 他现在可能在睡觉。

Might this be true? 这可能是真的吗？（该句通常表达为：Can/Could this be true?）
She may not go to the concert tonight. 今晚她可能不去听⾳乐会了。

The bedclothes catch fire and the whole house may be burnt down. 床上⽤品着⽕，整栋房⼦也许会被烧毁。

She may not be there today. 今天她可能不在那⼉。

The dialect of one city may be quite different from that of another. ⼀个城市的⽅⾔与另⼀个城市的⽅⾔可能⼗分不同。

Sometimes we might even need to spend some time leading in to a question or request.
有时我们或许需要花费⼀些时间来导⼊⼀个问题或请求。

[摘⾃《Go for itⅢ》P92]
★[特别注意]m a y与c a n表⽰推测时的区别
can和may均可以表⽰推测，can的语⽓要⽐may强。

can⽤于否定句和疑问句，may⽤于否定句和肯定句。

两者⽤于否定句的含义不同：can not表⽰“不可能”，may not 表⽰“可能不”。

试⽐较：
He can’t be a doctor. 他不可能是医⽣。

He may not be a doctor. 他可能不是医⽣。

三、m i g h t在虚拟语⽓的主句中构成谓语。

常与动词的完成式连⽤，即might have done，表⽰过去本来可以完成⽽实际上却未完成的动作。

If she had made better use of her time, she might have made much better achievement.
要是时间利⽤得更好些，她也许会取得更好的成绩。

He might have killed himself without their help. 要是没有他们的帮助，他可能早已丧命。

She might have expressed her true feeling at that time. 那时她也许以表达了她的真情了。

You were careless. You might have got hurt. 你很粗⼼，你当时会受伤的。

He came home alone. You shouldn’t have had him do that; he might have got lost.他独⾃回家。

你不该让她这样，他会迷路的。

You might have told me earlier about your illness. 你本该早点告诉我你的病情。

You might have come earlier. 你本该早点来。

四、m a y/m i g h t的固定习惯⽤法
1、表⽰祝愿时常⽤“may+主语+动词原形”结构。

May you have a happy life. 祝你⽣活幸福。

May you succeed. 祝你成功。

May you have a good trip. 祝你旅途愉快。

2、may/might as well…这种结构表⽰有礼貌的劝告，常译为“不妨”、“还是……的好”。

It’s too late. You might as well not go. 天已晚了，你最好不要⾛了。

There is nothing to do, so I may as well go to bed. 没什么事可做，我还是上床睡觉好了。

You may/might as well tell her the truth. 你还是把事实真相告诉她为好。

3、may/might well…“很可能……”、“ (完全)能”、“（满）可以”。

His appearance has changed so much that you may well not recognize him. 他的外貌变化如此之⼤，你很可能认不出他来。

m u s t/h a v e t o
⼀、m u s t/h a v e t o都可以表⽰义务，即“必须”、“应该”。

must强调说话者的主观看法，have to强调客观的需要，在回答带有must的问句时，否定回答常⽤need not (needn’t)或don’t have to, ⽽不是⽤must not.⽤于否定句时，mustn’t的意思是“不能、禁⽌、⼀定不要”，⽽不是“不必”。

如：The work must be finished as soon as possible. 这项⼯作必须尽快完成。

I must go now. 现在我该⾛了。

（主观看法）
--- Must I be home before eight o’clock?
--- Yes, you must. --- No, you needn’t. / No, you don’t have to.
All of the students will have to know how to use the computers in the future. 将来所有学⽣都必须懂得怎样使⽤电脑。

You can go out with your friends but you must come back before 11 at night. 你可以和朋友出去玩，但必须在晚上11点之前回来。

You mustn’t leave your books about, keep them in order. 你把书丢的到处都是。

把它们摆放整齐。

（mustn’t表⽰“禁⽌”）You don’t have to / don’t need to / needn’t tell him the truth if you don’t want to.如果你不想告诉他真相，就没⽐要告诉他。

I must ask you not to do that again. 我得劝他别那样做了。

You mustn’t say things like that. 你千万不要那样说话了。

--- Must he come here at once？他必须马上来着吗？
--- No, he needn’t /doesn’t have to. 不，他不必。

（don’t have to / don’t need to / needn’t表⽰没这个义务）
⼆、m u s t⽤来表⽰推测，即“⼀定”、“必定”。

这时must只能⽤在肯定句中，这种推测要⽐may肯定得多。

其否定形式mustn’t并不表⽰推测，只有“不能、禁⽌、⼀定不要”之意。

若要表⽰否定推测，常⽤can’t/couldn’t.
There must be some mistake. ⼀定是出什么差错了。

She must have been very young when she got married. 她结婚时⼀定很年轻。

It must have rained last night because it was wet in the street. 因为街道很湿，所以昨晚⼀定是下过⾬了。

He must be over sixty. 他⼀定60开外了。

对现在推测常⽤“must+动词原形”，表⽰“⼀定”。

You must be ill. I can see it from your face. 你准是病了，我从你的脸上可以看出来。

You must have the wrong number. There is no such a person. 你⼀定是搞错了，这⾥没有这样⼀个⼈。

对正在进⾏的⾏为进⾏推测常⽤“must be doing”，表⽰“⼀定正在……”.
Something must be burning. I can smell it. ⼀定是什么东西烧焦了，我能闻出来。

George must be sleeping now. 乔治现在可能在睡觉。

对将来的推测常⽤““must be doing”。

They must be arriving early this evening. 他们今晚⼀定会早些来的。

Bell must be leaving tomorrow. 贝尔明天⼀定⾛。

对过去的推测常⽤“must have done”或“must have been doing”结构。

You must have gone to bed late last night. Your eyes are red. 昨天晚上你⼀定睡得很晚，你的眼睛红红的。

Someone must have entered the room, for my books have been moved. 昨天⼀定有⼈进过这件屋⼦，因为我的书被动过了。

You must have read the book. You know the story very well. 你准读过这本书，你对这个故事很熟悉。

You must have lived here for years, for you know every place here. 你在这⾥⼀定住过很多年，因为你对这⾥的每⼀个地⽅都很熟悉。

Jeff must have been working hard for hours. He is too tired.杰夫⼀定⼯作好⼏个⼩时了，他现在⾮常累。

You must have been working for us a long time. 你⼀定等我们很长时间了。

★[特别提⽰]m u s t与h a v e t o的区别两者均可以表⽰“必须”，但两者有所不同：must表⽰说话的主观看法，⽆⼈称和时态的变化；
①have to 着重于表⽰客观的需要，含有“不得不”之意，有⼈称和时态的变化。

You must finish this today. 你今天⼀定要做完这件事。

You must say sorry to your parents. 你必须向你的⽗母道歉。

My eyesight isn’t very good. I have to wear glasses for reading. 我的视⼒不太好，看书时不得不戴眼镜。

②它们的否定意义不同：
must的否定式，mustn’t意为“⼀定不要”、“不允许”、“禁⽌”； have to的否定式don’t have to意为“不必”（=needn’t）试⽐较：You mustn’t tell him about it. 你⼀定不要告诉她这件事。

You don’t have to tell him about it. 你不必告诉她这件事。

③英国英语中常⽤have got to来叙述客观的情况。

have to是实义动词，其否定形式和疑问形式，都需要⽤do/did/does；
⽽have got to中have 本⾝就是助动词，其否定形式和疑问形式按助动词have的形式即可。

I can’t see things clearly. I have to wear glasses. 我看不清东西，只好戴眼镜。

They had to speed up, for the weather turned terrible. 天⽓变得糟糕起来，他们只好加快速度。

Do you have to do the work in such a way? 你必须以这种⽅式作这项⼯作吗？
Have you got to leave so early? 你必须这么早就⾛吗？
三、m u s t表⽰“偏要”、“硬要”、“偏执”、“固执”。

--- How old are you, madam? --- If you must know, I’m twice my son’s age.如果你⾮要知道，我是我⼉⼦年龄的2倍。

It can’t help. He must go with me. 没办法，她⾮要跟我去。

Many young people must have their own ways. 很多年轻⼈总是想怎么样就怎么样。

Why must you listen to him? 为什么你⾮要听他的呢？
As I was about to start to work, the telephone must ring. 我正要开始⼯作，电话偏偏响了。

o u g h t t o
情态动词ought to的形式
⼀、表⽰义务，即“应该”，和s h o u l d相近，其语⽓⽐s h o u l d强，带有责备和督促之意。

You don’t look well. You ought to go to see the doctor. 你⽓⾊不好，应该去瞧⼤夫。

You ought not to write so quickly. 你不应该写的如此潦草。

Oughtn’t we to give him a chance to try? 我们难道不应该给他⼀个尝试的机会吗？
Humans ought to stop polluting nature. ⼈类应该停⽌污染⼤⾃然。

You ought to make an apology to Joan. 你应该向Joan道歉。

We ought to learn more about our body and the fuel it needs to keep fit.
我们应该多了解我们的⾝体和它所需要的养分才能保持健康。

[摘⾃《⾼⼀英语教材下册》P4] ★ [注意] ought to与should在表⽰义务时同义。

在⽣活交际中⼈们多⽤should，should多表⽰⾃⼰的主观看法；
ought to则多反映客观情况，表⽰因责任、义务等该做的事，或要使⾃⼰的意见听起来像法律⼀样有⼒。

试⽐较： You are his father. You ought to take care of him. 你是他⽗亲，应当管他。

You should not ring her up. 你不宜打电话给他。

You ought to/should go and see Mary some time. 你应该找个时间去看看玛丽。

We ought to go and see Mary tomorrow, but I don’t think we have time.我们应该明天去看看玛丽，可我认为我们没有时间。

但多数情况下，⼆者常可互换。

如：
You shouldn’t/oughtn’t to talk like that. 你不应当这样谈话。

⼆、表⽰推测，即⾮常可能之事，意思是“⼀定会”、“该……”，其语⽓较，mu st弱，不如must那样肯定。

She ought to be home by now. 她现在该到家了.
Ask Tom, he ought to know. 去问Tom吧，它应该知道。

If we start right now, we ought to be able to get there on time. 如果我们现在动⾝，我们应该可以准时到达。

The seats ought to be enough for all the guests. 应该为客⼈提供⾜够的座位。

We ought to win. 我们⼀定会赢。

There is a fine sunset, it ought to be a fine day tomorrow. 今天有晚霞，明天应该是个好天。

三、o u g h t t o与动词不定式的完成式连⽤，即：“o u g h t t o h a v e d o n e”，表⽰对本来该做⽽未做之事的责难、后悔或遗憾之情。

You ought to have helped her. 你本该帮助她。

（却没有帮助她）
He ought to have returned these books to the library last week.他上星期就应该把这些书还给图书馆。

（却没有还书）
I ought not to have done it. 我本不该做这件事。

（却做了）
You are late. You ought to have arrived five minutes earlier. 你来迟了，你本应该早来五分钟。

You oughtn’t to have taken the city map. I’m familiar with each part.你本没有必要带地图的，我对这个城市的每⼀个地⽅都很
w i l l/w o u l d
⼀、表⽰意愿、意志，⽤于各种⼈称，w i l l指将来，w o u l d指过去将来。

We will help him if he asks us to. 假如他请求我们的帮助，我们就愿帮他。

He won’t go to the countryside. 他不愿去乡村。

I promised that I would do my best. 我答应会尽我的最⼤努⼒。

They said that they would tell us all about it. 他们说愿意将事情的全部告诉我们。

He wouldn’t go, so I went instead of him. 他不愿意去，所以我代替他去了。

⼆、表⽰征求意见或请求。

主要⽤于第⼆⼈称的疑问句中，will/would均可⽤，would此时并不表⽰过去，⽽表⽰委婉语⽓。

Will you come in? 请进来好吗？
Won’t you send for a doctor? 你不要派⼈找医⽣来吗？
Will/Would you close the window? 请把窗户关上好不好？
I’m going to the library. Will you go with me? 我马上去图书馆。

你愿意跟我⼀起去吗？
Would you like some bananas? 想吃点⼉⾹蕉吗？ (指现在)
Will you give him a message when you see him? 见到他时，请你通知他⼀下好吗？
Would you mind closing the windows? 请把窗户关上好吗？
Will you come this way, please? 请你⾛这边好吗？
Won’t you come in and take a seat? We’ve already started the class.你怎么不进来找个位⼦坐下？我们已经上课了。

Would you open the window, please? I feel it is a little stuffy here. 你愿意打开窗户吗？我感觉这⾥有点闷。

三、表⽰习惯和倾向性。

will表⽰现在的习惯，would表⽰过去的习惯，带有主观性。

⽐used to更正式，并没有“现在已⽆此习惯”的含义。

He will have a cup of coffee in the afternoon. 他下午就喝⼀杯咖啡。

When I was a child, I would often go swimming in the river. 我⼩时候经常去河⾥游泳。

He will sit there for hours doing nothing at all. 他常常⼏个⼩时坐在那⼉⽆所事事。

When I was a student, I would take a walk along the country road after class. 当学⽣时，放学后我常常沿着乡间⼩路散步。

I used to smoke, but now I don’t at all. 过去我常常抽烟，但现在我⼀点也不抽了。

This old man is very strange. He will sit for hours without saying anything.这位⽼⼈很奇怪，他会坐在那⼉⼏个⼩时不说话。

We would sit around Grandpa after supper, listening to his stories.过去晚饭后我们总会坐在爷爷周围，听他讲故事。

★[特别提⽰]u s e d t o与w o u l d表⽰“过去总……”的⽤法区别
would⽤于过去，带有主观性；used to 具有客观性，着眼于与现在的对⽐，可与过去的时间状语连⽤。

She would feel lost whenever she got into trouble. ⼀遇到困难，她总是感到⾮常失落。

He would phone me on Sundays. 他总是星期天给我打电话。

I used to be very fond of music when I was young. 我年轻时很喜欢⾳乐。

四、表⽰规律性的“注定会”。

People will die without water or air, which is still in some way polluted.⼈离开⽔和空⽓将会死，但空⽓和⽔依然以某种⽅式被
You will regret forever if you lose this golden chance. 错过这次⼤好机会，你注定会懊悔的。

五、w i l l/w o u l d⽤于固定习惯⽤法中。

I’d rather do it myself. 这事我宁愿⾃⼰做。

（⽤于would rather中）
He’d sooner die than let me think he was a coward. 他宁死也不愿让我认为他是⼀个懦夫。

（⽤于would sooner中）Would you mind my staying here for a while? 我在这⼉呆会⼉，你介意吗？（⽤于Would…mind中）
---Would you like to come to my party tomorrow? (⽤于would like to)
--- Yes, I’d love to. (⽤于would love to)
s h a l l/s h o u l d
⼀、表⽰征询意见。

shall⽤于第⼀、三⼈称的疑问句中，should⽤于第⼀⼈称的疑问句中，should⽐shall的语⽓更委婉。

Shall I change into the evening dress for your party? 我可以换上晚礼服参加你的晚会吗？
Shall we put off the sports meet until next month? 我们能否将运动会推迟到下个⽉？
Shall Tom go there with me tomorrow? 汤姆明天可以和我⼀起去吗？
Henry is waiting outside. Shall he come in, sir? 亨利正在门外等着，可以让他进来吗，先⽣？
Shall I open the door? 我开门好吗？
Shall we take umbrellas with us? 我们要不要带⾬伞？
Where shall I wait for you? 我在哪⼉等你好呢？
Shall we start the meeting now? 我们现在开会好吗？
What shall he do next？他下⼀步⼲什么好？
What should we do now? 我们现在该怎么办？
Should I turn off the radio? 我可以关掉收⾳机吗？
⼆、s h o u l d常⽤来表⽰义务。

含有劝告、建议之意，常译作“应该”，多表达说话⼈⾃⼰的主观看法，且通常指将来。

I think today’s children should really learn to respect their elders. 我认为今天的孩⼦应当好好学习尊重长者。

You should keep your promise. 你应该信守承诺。

Young people should learn how to use computers. 年轻⼈应该学会如何使⽤计算机。

We should never forget the history. 我们永远都不应该忘记历史。

Good snacks should not have too much fat or sugar. 好的点⼼脂肪和糖的含量不应该太多。

[摘⾃⾼⼀英语下Unit 1] 三、s h o u l d表⽰虚拟。

⽤于完成式的肯定句中，即should have done,表⽰过去应该做⽽未做的事。

⽤于完成式的否定句中，即shouldn’t have done,表⽰不应该完成但已完成的事。

He looks very tired. He should have had a good rest at home. 他看上去很累了，本应该呆在家⾥好好休息。

As an adult, he shouldn’t have misunderstood it. 作为成年⼈，他本来就不应该误解这件事。

You should have invited me to the party yesterday, I had expected you to.昨天你应该邀请我参加宴会的，我本预料你会的。

Jim shouldn’t have done all the work within one day. There was still time.Jim本不应该把所有的⼯作⼀天做完的，当时还有时间。

d a r e
dare既可以⽤作情态动词，也可以作实义动词。

⽤作情态动词时，它只有⼀种形式，后跟动词原形，主要⽤于否定句、疑问句
和条件句中；⽤作实义动词时，它有动词的全部形式，即dares、daring、dared,后跟带有to的不定式。

“敢于”。

⼀、d a r e作情态动词时，⽆⼈称和数的变化，加动词原形。

Dare he tell them what he knows? 他敢告诉他们它所知道的吗？
I’m afraid you dare not/ daren’t do such a thing. 恐怕你不敢做这样的事。

You will be punished if you dare break the rules. 如果你敢违反规定，你会受到惩罚的。

How dare they do such a thing? 他们怎么敢做出这样事？
I scarcely dare think of it. 这件事我简直连想都不敢想。

She was so sensitive that no one dare tell her the sad news. 她如此敏感，以致没⼈敢把这噩耗告诉她。

I daren’t have done it yesterday, but I think I dare now. 我昨天不敢做这件事，但我想现在敢做了。

[注]现在常把dare⽤作及物动词。

⼆、d a r e作实义动词时，有⼈称和数的变化，加带t o的不定式。

She was so sensitive that no one dared to tell her the sad news. 她如此敏感，以致没⼈敢把这噩耗告诉她。

How did they dare to do such a thing? 他们怎么敢作出这样的事？
This student doesn’t dare to raise any question in class. 这个学⽣不敢在课堂上提出任何问题。

I suppose he dares to tell the manager the truth. 我想他敢告诉经理事情的真相。

Do you dare to drive a car in such a crowded road? 你敢在这么拥挤的街道上开车吗？
I d on’t dare to use the phone in school, because they will take it away from me.
我不敢在学校⾥使⽤⼿机，因为他会被没收的。

[摘⾃《⾼⼀英语教材上册》P59]
三、⽤于固定习语中。

I dare say 已成为习惯⽤法，“也许、恐怕、我想”。

It will rain this afternoon, I dare say. 我想今天下午会下⾬。

My son is not at home, but I dare say he will come back before long.我⼉⼦现在不在家，不过我想他不久他就会回来。

[除此习语之外，dare⼀般不⽤于肯定式的陈述句中。

]
n e e d
need同dare⼀样，既可以⽤作情态动词，也可以作实义动词。

⽤作情态动词时，它只有⼀种形式，后跟动词原形，主要⽤于否定句、疑问句和条件句中；⽤作实义动词时，它有动词的全部形式，即needs、needing、needed,后跟不带to的不定式，可⽤于⼀切句式。

⼀、n e e d作情态动词时，⽆⼈称和数的变化，加动词原形。

You need not meet him unless you would like to. 除⾮你愿意，你不需要见他。

---Need I come? 我需要来吗？
--- Yes, you must. 需要。

/ No, you needn’t. 不需要。

I hardly need say how much we missed you. 不⽤说，我们是多么想念你啊！
---Need I tell him everything that happened to his parents?
--- Yes, you must. 需要。

/ No, you needn’t. 不需要。

You needn’t be told twice about one single thing. 同⼀件事不必对你说两遍。

The question needn’t have been discussed. 此问题本来不需要讨论。

（实际上已讨论了。

）
I actually needn’t have bought so much wine---only three people came. 其实我当初没必要买这么多酒，只来了三个⼈。

We needn’t have bought the presents. 我们本来不需要买礼物的。

（实际上却买了。

）
[情态动词need⽤于完成式，即needn’t have done，表⽰本不需要完成的动作却完成了。

]
⼆、n e e d作实义动词，有⼈称和数的变化，加带t o的不定式。

You need to be careful. 你得⼩⼼点。

You don’t need to be so worried. 你不必如此担⼼。

= You needn’t be so worried.
Do I need to say my telephone number again? 我需要再说⼀遍电话号码吗？= Need I say my telephone number again? Doesn’t he need to come again?=Does he not need to come again?=Needn’t he come again?=Need he not come again?
h a d b e t t e r
had better 主要⽤来表⽰劝告和建议，其后跟动词原形。

had better 和汉语的“你最好……”意义略有不同。

You’d better 是⼀种命令⼝⽓，含有“我说了，你得听”的味道，故下级对上级、晚辈对长辈不宜使⽤这种结构。

[肯定式] You’d better try it again if you fall this time. 如果你这次失败了，最好还是在试⼀次。

I’m afraid you’d better have a good rest to save energy for tomorrow’s work.恐怕⽐最好得休息⼀下，为明天的⼯作积蓄些⼒量。

When we choose what to buy or eat, we had better think whether the food will give us the nutrients we need.
当选定买什么、吃什么的时候，我们最好考虑⼀下，该⾷物是否能提供我们所需的营养。

[摘⾃《⾼⼀英语教材下册》P3] [否定式]You had better not quarrel with your neighbors whatever happens. 不管发⽣什么事，你最好不要和邻居吵架。

[疑问式] Had I better not tell anyone about today’s discussion?
=Hadn’t I better tell anyone about today’s discussion?
=Had I better not tell anyone about today’s discussion? 我最好不要把今天所讨论的内容告诉任何⼈吗？
情态动词近20年⾼考真题再现
1. A left-luggage office is a place where bags ___ be left for a short time, especially at a railway station.[03全国]
A. should
B. can
C. must
D. will
2. How ____ you say that you really understand the whole story if you have covered only part of the article? [03上海]
A. can
B. must
C. need
D. may
3. You might just as well tell the manufacturer that male customers ___ not like the design of the furniture.[04上海]
A. must
B. shall
C. may
D. need。