11.2　情态动词

11.2.1　can的用法

can表示现在或将来的情况，主要表示：

1) 能力（即能做某事）：

Can you ride a bicycle? 你能骑自行车吗？

She can run very fast. 她能跑得很快。

Who can answer this question? 谁能回答这个问题？

I can't pay you today. Can you wait till tomorrow? 我今天不能给你钱，你能等到明天吗？

I can't promise anything, but I'll do what I can. 我不能许诺什么，但我将尽力而为。

be able to可以表示同样意思，并还可明确表示未来时间，甚至用于完成时态：

Our baby will be able to walk in a few weeks. 我们的宝宝几周后就能走路了。

Since his accident he hasn't been able to walk properly. 出事之后他一直未能正常走路。

2) 可能性（可以、可能做某事）：

Can you help me with the box? 你能帮我抬这箱子吗？

We can eat in a restaurant. 我们可以在餐馆吃饭。

I can call you tomorrow. 我可以明天给你打电话。

I'm afraid I can't go with you. 恐怕我没法和你一道去。

3) 有时会（不经常如此）：

You can be very annoying. 有时你会很让人生气。

He can be very tactless sometimes. 他有时讲话很笨拙。

Scotland can be very cold. 苏格兰有时很冷。

It can be quite windy on the hills. 山上有时风很大。

Wasp stings can be very painful. 黄蜂蜇人有时很疼。

4) （用于否定句及疑问句）可能：

That can't be Mary—she's in hospital. 那不可能是玛丽，她在住院。

Surely you can't be hungry. You've only just had lunch. 你肯定不会饿的，你刚刚吃过午饭。

There's someone outside—who can it be? 外边有人，这能是谁呢？

Can he still be alive after all these years? 过了这么多年他还活着吗?后面有时跟不定式的完成形式或进行式：

He can't have taken it upstairs. 他不可能把它拿上楼了。

She can't be telling the truth. 她讲的不可能是真话。

What can she be doing at this time? 此时她会在干什么呢？

5) 表示“允许（做某事）”（和may的意思差不多，在日常口语中can用得更多）：

You can (may) park here. 你可以把车停在这里。

You can (may) take the book home. 你可以把这书带回家。

They can phone the police. 他们可以给警察打电话。

This sort of thing can't go on! 这种事情不能继续下去了。

You can't smoke here. 你不能在这里抽烟。

11.2.2　could的用法

could主要有下面用法：

1) 作为can的过去式，表示过去情况：

a. 表示能力：

When I was young I could climb any tree in the forest. 小时候森林里的树我都能爬上去。

I could drive a car before I left school. 我中学毕业前就会开车。

He read the message but couldn't understand it. 他看了电报但没看懂。

I could see her through the window. 从窗口我可以看见她。

She couldn't answer the teacher's question. 她回答不上老师的问题。

这时也可用was (were) able to,甚至用过去完成形式：

I was able to see her through the window. 从窗口我可以看见她。

He said he had lost his passport and hadn't been able to leave the country. 他说他的护照丢了，不能离境。

b. 表示可能性：

It was so dark we could see nothing. 天那样黑，我们什么也看不见。

He said he couldn't come. 他说他不能来。

I thought I could smell something burning. 我想我可以闻到糊味。

He could be pretty naughty when he was a child. 他小时候有时很淘气。

2) 用来代替can，说明现在情况：

a. 婉转地提出请求、想法、建议等：

Could (Can) you send me an application form? 你可否寄我一张申请表？

Could you show me the way? 你可否告诉我怎样去？

Couldn't you come a little earlier? 你不能稍微早一点来？

I could get you a copy. 我可以帮你找一份。

I could do it now if you like. 如果你愿意我现在就可以做。

You could be right, I suppose. 我想你可能是对的。

We could write a letter to the director. 我们可以给主管写一封信。

You could have a nursery here. 你可以在这里办一个托儿所。

b. 用于疑问及否定句表示惊异、不相信等：

Could this be true? 这能是真的吗？

How could you be so careless? 你怎么能这样粗心大意？

后面的不定式常可用完成形式或进行式：

I couldn't have left it on the bus. 我不可能把它丢在公共汽车上。

They couldn't have left so soon. 他们不可能这么早就走了。

Could he still be working at this late hour? 这么晚了他还在工作吗？

Could you have been waiting so long? 你竟然等了这么久吗？

3) 用于虚拟条件句：

You could get into university if you applied. 如申请的话，你能进大学。

If you tried you could do that work. 如果你试试你可以干这工作。

I could have earned something if I had meant to. 如果我真有心这样做，我是可以挣些钱的。

Even if he had been there, he couldn't have helped you. 即使他在那里，他也帮不了你的忙。

Why didn't you apply for the job? You could have got it. 你为什么没申请这份工作？你是可以得到它的。

4) could+不定式的完成形式，可用来谈过去情况：

a. 表示“那时（不）可能”：

The money has disappeared! Who could have taken it? 钱不见了，是谁拿了呢？

Tom could have taken it;he was here alone yesterday. 可能是汤姆拿了，昨天他一人在此。

Don't worry—they could have just forgotten to phone. 别着急，可能他们只是忘了打电话。

She could not have been more than six then. 那时她不可能超过六岁。

b. 表示“本来可以”或“差点就”：

He could have sent a message. 他本来可以捎个口信来的。

I could have lent you the money. Why didn't you ask me? 我本来可以借这笔钱给你的，你怎么没向我借？

The accident could have been prevented. 这事故本来是可以防止的。

I could have died laughing. 我差点笑死了。

c. 提出婉转的批评：

You could have been more considerate. 你本可考虑得更周到些。

You could have started a little earlier. 你本可稍早一点动身的。

They could have let me know they were going to be late. 他们本可提早通知我他们将要晚点。

You could have told me beforehand. 你本可事先告诉我的。

11.2.3　may的用法

may主要有下面几种用法：

1) 用来提出问题，问可不可以：

May I use your phone? 我能用一下你的电话吗？

May I come in? 我可以进来吗？

May I leave this with you? "Yes, you may." “我可以把东西放你这儿吗？”“可以。”

I may leave now, mayn't I? 我现在可以走了，对吧？

May I come round in the afternoon？——Yes, please do. 我下午来好吗？ ——行，好的。

2) 用于陈述句，表示“可以”或“不可以”：

You may only borrow books for two weeks. 书你只能借两个星期。

You may come if you wish. 如果你愿意你可以来。

Passengers may cross by the footbridge. 行人过街可走天桥。

You may not take photographs in the museum. 博物馆内不得拍照。

Dogs may not be taken into these carriages. 不得携狗进入这些车厢。

3) 表示“可能”：

Anna may know Tom's address. 安娜可能知道汤姆的地址。

Jim may emigrate. 吉姆可能要移居国外。

He may have gone abroad. 他可能出国了。

They may be waiting at the station. 他们可能正等在车站。

I may be going to Europe next year. 我明年或许去欧洲。

4) 用在某些状语从句中：

Speak clearly so that they may understand you. 讲清楚些以便他们能听明白。

However frightened you may be yourself, you must remain calm. 不管你自己多么害怕，你必须保持镇静。

However much she may desire it, she can't express her sympathetic feelings.她无法表达她的同情心，不管她多么想这样做。

Try as he may, he will not pass the examination. 不管多努力，他都无法通过考试。

Shut the window for fear (that) it may rain. 把窗子关上，以防下雨。

He's decided to get a college education, come what may. 不管发生什么情况，他都决定要上大学。

5) 表示祝愿：

May you be happy! 祝你幸福！

May God be with you. 愿上帝与你同在。

Long may she live to enjoy her good fortune! 祝她长寿好运！

6) 用于某些成语中：

a. may as well 不妨：

You may as well bring me a chocolate too. 你不妨也给我带一块巧克力来。

If that's the case, I may as well try. 如果情况是这样，我不妨一试。

b. may...but 或许…但是：

They may be good reports, but they seem to lack facts. 这些报告或许写得不错，但似乎缺乏事实。

Oxford may have changed a lot in recent years, but it's still a beautiful city.牛津近年来可能改变很多，但它仍是一座美丽的城市。

c. may well... 很可能…：

His appearance has changed so much that you may well not recognize him.他的外貌变了很多，你可能都认不出他了。

The team may well have won the football match, but I don't know because I wasn't there. 那支球队很可能赢得了足球赛，但我不知道，因为我没去。

11.2.4　might的用法

might主要有下面这些用法：

1) 用作may的过去式：

a. 表示“可以”

I asked if I might go home half an hour earlier today. 我问我是否可以提早半小时回家。

He asked if he might use the phone. 他问是否可以用一下电话。

He suggested one or two books which they might buy. 他推荐了一两本他们可以买的书。

I thought you might stay with us. 我想你可以住我们这儿。

b. 表示“可能”（或许会）：

He said he might be late. 他说他可能晚到。

She told me that she might go to Hawaii this winter. 她告诉我她今年冬天可能去夏威夷。

I guessed he might come tomorrow. 我猜他可能明天来。

c. 用在某些状语从句中：

I did this so that I might have time to prepare my manuscript. 我这样做以便我有时间把稿子准备好。

She was not allowed to go to bed, lest she might be needed. 没让她去睡觉以防不时之需。

I lent him £50 in order that he might go for a holiday. 我借给他五十英镑，以便他能去度假。

Marina made up her mind that, come what might, she would stay there. 玛丽娜下了决心，不管发生什么情况，她都留在那里。

Try as she might, she could not persuade her friends to go. 不管她怎样想办法，都不能说动她的朋友们去。

2) 用来代替may，谈现在的情况，口气比may更婉转些：

a. 表示“可以”（用may时更多一些）：

Might (May) I have a little brandy? 可否给我一点白兰地？

In that case you might bring your father to live with us. 如果那样你可以把你父亲接来和我们一道住。

You might just call at the chemist on the way home. 在回家路上你可以到药房去一下。

Might I use your phone (say something)? 我能用一下你的电话吗（我能说几句话吗）？

b. 表示“可能”、“或许”：

He might tell his wife. 他可能会告诉他妻子。

She might not believe your story. 她可能不会相信你的说法。

He might have gone home. 他或许回家了。

Eva might not have seen him yesterday. 昨天夏娃可能没见到他。

She might still be waiting there. 她可能还在那里等。

We might be going to Spain on holiday this year. 今年我们或许会去西班牙度假。

She might have been taken ill quite suddenly. 她或许是突然生病了。

3) 用于虚拟条件句：

If I had known the film was about Wales, I might have gone to see it. 要是我知道这部影片是关于威尔士的，我可能就去看了。

The pills might have helped him, if he'd taken them regularly. 如果这些药片他定时吃，可能对他是有效的。

If you invited him, he might come. 如果你邀请他，他可能会来。

If you didn't mind, we might go there. 如果你不介意，我们可能去那里。

It was really very dangerous. You might have injured him. 真的是很悬，你会让他受伤的。

4) 表示轻微的埋怨或批评：

They might at least have phoned if they're not coming. 要是他们不来了，至少可以打个电话来嘛。

You might tell me if you're going to be late. 如果你要晚到，你可以告诉我一声。

Honestly, you might have told me! 说真的，你本可告诉我一声的。

5) 用于might as well （意思和may as well差不多），表示“不妨…”：

We might (may) as well go together. 我们不妨一块儿去。

You might as well phone the customer service department about it. 你不妨给客户服务部打个电话谈谈这事。

Shall we walk？——We might as well. 咱们步行去吗？——不妨走走吧。

11.2.5　must的用法

must主要有下面用法：

1) 表示“必须”、“一定要”、“得…”（多指现在或将来情况）：

You must cut down on smoking. 你必须少抽些烟。

Passengers must cross the line by the footbridge. 旅客必须由天桥穿越铁路。

I must remember to go to the bank today. 我今天一定要记住去银行。

Must we finish the exercise today? "Yes, you must. (No, you don't have to.)" “我们今天必须做完这项练习吗？”“是的，必须做完（不，不必做完）。”

I'm afraid I must be going. 我看我得走了。

The work must be finished by the end of the week. 这工作周末必须完成。

Δ否定形式表示“不得”、“一定不要”：

You mustn't take photographs in here. It's forbidden. 此处不得拍照，这是禁止的。

Cars must not park in front of the entrance. 大门前不得停车。

We mustn't be late, must we? 我们不得迟到，对吧？

You mustn't drive without a license. 你不得无照驾车。

Δ表示过去情况用had to更清楚一些，虽然must也可以表示过去情况：

I had to go to see the dentist. 我得去看牙医。

When did you have to leave? 你什么时候得动身？

She asked him if she must (had to) work overtime. 她问他她是否一定要加班。

2) 表示推想，可译作“一定”、“准是”等：

You must be hungry. Have something to eat. 你一定饿了，吃点东西吧。

They must be twins. 他们一定是双胞胎。

The police are stopping all cars. They must be looking for the escaped prisoner. 警察让所有的车都停下来，他们准是在搜寻逃犯。

There's a lot of noise from next door. They must be having a party. 隔壁那屋很嘈杂，他们准是在开晚会。

I can't find my cheque book. I must have left it at home. 我找不到我的支票本，准是留在家里了。

We must have read the same report. 我们一定是看了同一份报告。

You must have been thinking of something. 你准是在想什么心事。

3) 表示“应当（做某事）”（和should， ought的意思差不多）：

You really must see that film. It's wonderful. 你真应该去看这部电影，非常精彩。

You must see what the authorities have to say. 你应当去了解一下当局怎么说。

We must think of this matter very seriously. 我们应当认认真真地考虑此事。

You must recognize that we can't allow such behaviour. 你应当明白我们不容许这种行为。

11.2.6　ought的用法

ought总是和to一道用，表示：

1) 应该，应当（意思接近于should）：

I ought to write to him today. 我今天应当给他写信。

You ought to read this book. It's marvellous! 这本书你应当看看，真是好极了。

What ought I to say to him? 我该对他说什么呢？

You ought to visit your parents more often. 你应当更多地探望你的父母。

You oughtn't to make private phone calls in work time. 在工作时间你不应该打私人电话。

I knew I ought to write to her. 我知道我应当给她写信。

Ought I to write to say thank you? 我是不是该写信去致谢？

Δ 后面的不定式可用完成、进行或被动形式：

They ought to have stopped at the traffic lights. 在红绿灯前他们本应停车。

You ought to have come to the meeting. 你是应该来开会的。

We ought to be leaving now. 我们现在该走了。

He oughtn't to have been driving so fast. 他是不应当把车开这么快的。

He ought to be isolated. 他应当被隔离。

Something ought to be done about it. 对此应当想些办法。

2) 表示揣测：

She ought to pass her test. 她应当能通过测试。

He ought to be there (to have arrived) by now. 他现在应该已经到了。

The water ought to have boiled by now. 现在水应该开了。

We ought to be hearing from Wendy soon. 我们不久就应可以收到温迪的信。