can表示現(xiàn)在或將來的情況,主要表示:
1) 能力(即能做某事):
Can you ride a bicycle? 你能騎自行車嗎?
She can run very fast. 她能跑得很快。
Who can answer this question? 誰能回答這個問題?
I can't pay you today. Can you wait till tomorrow? 我今天不能給你錢,你能等到明天嗎?
I can't promise anything, but I'll do what I can. 我不能許諾什么,但我將盡力而為。
be able to可以表示同樣意思,并還可明確表示未來時間,甚至用于完成時態(tài):
Our baby will be able to walk in a few weeks. 我們的寶寶幾周后就能走路了。
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? 你能幫我抬這箱子嗎?
We can eat in a restaurant. 我們可以在餐館吃飯。
I can call you tomorrow. 我可以明天給你打電話。
I'm afraid I can't go with you. 恐怕我沒法和你一道去。
3) 有時會(不經常如此):
You can be very annoying. 有時你會很讓人生氣。
He can be very tactless sometimes. 他有時講話很笨拙。
Scotland can be very cold. 蘇格蘭有時很冷。
It can be quite windy on the hills. 山上有時風很大。
Wasp stings can be very painful. 黃蜂蜇人有時很疼。
4) (用于否定句及疑問句)可能:
That can't be Mary—she's in hospital. 那不可能是瑪麗,她在住院。
Surely you can't be hungry. You've only just had lunch. 你肯定不會餓的,你剛剛吃過午飯。
There's someone outside—who can it be? 外邊有人,這能是誰呢?
Can he still be alive after all these years? 過了這么多年他還活著嗎?后面有時跟不定式的完成形式或進行式:
He can't have taken it upstairs. 他不可能把它拿上樓了。
She can't be telling the truth. 她講的不可能是真話。
What can she be doing at this time? 此時她會在干什么呢?
5) 表示“允許(做某事)”(和may的意思差不多,在日??谡Z中can用得更多):
You can (may) park here. 你可以把車停在這里。
You can (may) take the book home. 你可以把這書帶回家。
They can phone the police. 他們可以給警察打電話。
This sort of thing can't go on! 這種事情不能繼續(xù)下去了。
You can't smoke here. 你不能在這里抽煙。
could主要有下面用法:
1) 作為can的過去式,表示過去情況:
a. 表示能力:
When I was young I could climb any tree in the forest. 小時候森林里的樹我都能爬上去。
I could drive a car before I left school. 我中學畢業(yè)前就會開車。
He read the message but couldn't understand it. 他看了電報但沒看懂。
I could see her through the window. 從窗口我可以看見她。
She couldn't answer the teacher's question. 她回答不上老師的問題。
這時也可用was (were) able to,甚至用過去完成形式:
I was able to see her through the window. 從窗口我可以看見她。
He said he had lost his passport and hadn't been able to leave the country. 他說他的護照丟了,不能離境。
b. 表示可能性:
It was so dark we could see nothing. 天那樣黑,我們什么也看不見。
He said he couldn't come. 他說他不能來。
I thought I could smell something burning. 我想我可以聞到糊味。
He could be pretty naughty when he was a child. 他小時候有時很淘氣。
2) 用來代替can,說明現(xiàn)在情況:
a. 婉轉地提出請求、想法、建議等:
Could (Can) you send me an application form? 你可否寄我一張申請表?
Could you show me the way? 你可否告訴我怎樣去?
Couldn't you come a little earlier? 你不能稍微早一點來?
I could get you a copy. 我可以幫你找一份。
I could do it now if you like. 如果你愿意我現(xiàn)在就可以做。
You could be right, I suppose. 我想你可能是對的。
We could write a letter to the director. 我們可以給主管寫一封信。
You could have a nursery here. 你可以在這里辦一個托兒所。
b. 用于疑問及否定句表示驚異、不相信等:
Could this be true? 這能是真的嗎?
How could you be so careless? 你怎么能這樣粗心大意?
后面的不定式??捎猛瓿尚问交蜻M行式:
I couldn't have left it on the bus. 我不可能把它丟在公共汽車上。
They couldn't have left so soon. 他們不可能這么早就走了。
Could he still be working at this late hour? 這么晚了他還在工作嗎?
Could you have been waiting so long? 你竟然等了這么久嗎?
3) 用于虛擬條件句:
You could get into university if you applied. 如申請的話,你能進大學。
If you tried you could do that work. 如果你試試你可以干這工作。
I could have earned something if I had meant to. 如果我真有心這樣做,我是可以掙些錢的。
Even if he had been there, he couldn't have helped you. 即使他在那里,他也幫不了你的忙。
Why didn't you apply for the job? You could have got it. 你為什么沒申請這份工作?你是可以得到它的。
4) could+不定式的完成形式,可用來談過去情況:
a. 表示“那時(不)可能”:
The money has disappeared! Who could have taken it? 錢不見了,是誰拿了呢?
Tom could have taken it;he was here alone yesterday. 可能是湯姆拿了,昨天他一人在此。
Don't worry—they could have just forgotten to phone. 別著急,可能他們只是忘了打電話。
She could not have been more than six then. 那時她不可能超過六歲。
b. 表示“本來可以”或“差點就”:
He could have sent a message. 他本來可以捎個口信來的。
I could have lent you the money. Why didn't you ask me? 我本來可以借這筆錢給你的,你怎么沒向我借?
The accident could have been prevented. 這事故本來是可以防止的。
I could have died laughing. 我差點笑死了。
c. 提出婉轉的批評:
You could have been more considerate. 你本可考慮得更周到些。
You could have started a little earlier. 你本可稍早一點動身的。
They could have let me know they were going to be late. 他們本可提早通知我他們將要晚點。
You could have told me beforehand. 你本可事先告訴我的。
may主要有下面幾種用法:
1) 用來提出問題,問可不可以:
May I use your phone? 我能用一下你的電話嗎?
May I come in? 我可以進來嗎?
May I leave this with you? "Yes, you may." “我可以把東西放你這兒嗎?”“可以。”
I may leave now, mayn't I? 我現(xiàn)在可以走了,對吧?
May I come round in the afternoon?——Yes, please do. 我下午來好嗎? ——行,好的。
2) 用于陳述句,表示“可以”或“不可以”:
You may only borrow books for two weeks. 書你只能借兩個星期。
You may come if you wish. 如果你愿意你可以來。
Passengers may cross by the footbridge. 行人過街可走天橋。
You may not take photographs in the museum. 博物館內不得拍照。
Dogs may not be taken into these carriages. 不得攜狗進入這些車廂。
3) 表示“可能”:
Anna may know Tom's address. 安娜可能知道湯姆的地址。
Jim may emigrate. 吉姆可能要移居國外。
He may have gone abroad. 他可能出國了。
They may be waiting at the station. 他們可能正等在車站。
I may be going to Europe next year. 我明年或許去歐洲。
4) 用在某些狀語從句中:
Speak clearly so that they may understand you. 講清楚些以便他們能聽明白。
However frightened you may be yourself, you must remain calm. 不管你自己多么害怕,你必須保持鎮(zhèn)靜。
However much she may desire it, she can't express her sympathetic feelings.她無法表達她的同情心,不管她多么想這樣做。
Try as he may, he will not pass the examination. 不管多努力,他都無法通過考試。
Shut the window for fear (that) it may rain. 把窗子關上,以防下雨。
He's decided to get a college education, come what may. 不管發(fā)生什么情況,他都決定要上大學。
5) 表示祝愿:
May you be happy! 祝你幸福!
May God be with you. 愿上帝與你同在。
Long may she live to enjoy her good fortune! 祝她長壽好運!
6) 用于某些成語中:
a. may as well 不妨:
You may as well bring me a chocolate too. 你不妨也給我?guī)б粔K巧克力來。
If that's the case, I may as well try. 如果情況是這樣,我不妨一試。
b. may...but 或許…但是:
They may be good reports, but they seem to lack facts. 這些報告或許寫得不錯,但似乎缺乏事實。
Oxford may have changed a lot in recent years, but it's still a beautiful city.牛津近年來可能改變很多,但它仍是一座美麗的城市。
c. may well... 很可能…:
His appearance has changed so much that you may well not recognize him.他的外貌變了很多,你可能都認不出他了。
The team may well have won the football match, but I don't know because I wasn't there. 那支球隊很可能贏得了足球賽,但我不知道,因為我沒去。
might主要有下面這些用法:
1) 用作may的過去式:
a. 表示“可以”
I asked if I might go home half an hour earlier today. 我問我是否可以提早半小時回家。
He asked if he might use the phone. 他問是否可以用一下電話。
He suggested one or two books which they might buy. 他推薦了一兩本他們可以買的書。
I thought you might stay with us. 我想你可以住我們這兒。
b. 表示“可能”(或許會):
He said he might be late. 他說他可能晚到。
She told me that she might go to Hawaii this winter. 她告訴我她今年冬天可能去夏威夷。
I guessed he might come tomorrow. 我猜他可能明天來。
c. 用在某些狀語從句中:
I did this so that I might have time to prepare my manuscript. 我這樣做以便我有時間把稿子準備好。
She was not allowed to go to bed, lest she might be needed. 沒讓她去睡覺以防不時之需。
I lent him £50 in order that he might go for a holiday. 我借給他五十英鎊,以便他能去度假。
Marina made up her mind that, come what might, she would stay there. 瑪麗娜下了決心,不管發(fā)生什么情況,她都留在那里。
Try as she might, she could not persuade her friends to go. 不管她怎樣想辦法,都不能說動她的朋友們去。
2) 用來代替may,談現(xiàn)在的情況,口氣比may更婉轉些:
a. 表示“可以”(用may時更多一些):
Might (May) I have a little brandy? 可否給我一點白蘭地?
In that case you might bring your father to live with us. 如果那樣你可以把你父親接來和我們一道住。
You might just call at the chemist on the way home. 在回家路上你可以到藥房去一下。
Might I use your phone (say something)? 我能用一下你的電話嗎(我能說幾句話嗎)?
b. 表示“可能”、“或許”:
He might tell his wife. 他可能會告訴他妻子。
She might not believe your story. 她可能不會相信你的說法。
He might have gone home. 他或許回家了。
Eva might not have seen him yesterday. 昨天夏娃可能沒見到他。
She might still be waiting there. 她可能還在那里等。
We might be going to Spain on holiday this year. 今年我們或許會去西班牙度假。
She might have been taken ill quite suddenly. 她或許是突然生病了。
3) 用于虛擬條件句:
If I had known the film was about Wales, I might have gone to see it. 要是我知道這部影片是關于威爾士的,我可能就去看了。
The pills might have helped him, if he'd taken them regularly. 如果這些藥片他定時吃,可能對他是有效的。
If you invited him, he might come. 如果你邀請他,他可能會來。
If you didn't mind, we might go there. 如果你不介意,我們可能去那里。
It was really very dangerous. You might have injured him. 真的是很懸,你會讓他受傷的。
4) 表示輕微的埋怨或批評:
They might at least have phoned if they're not coming. 要是他們不來了,至少可以打個電話來嘛。
You might tell me if you're going to be late. 如果你要晚到,你可以告訴我一聲。
Honestly, you might have told me! 說真的,你本可告訴我一聲的。
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. 我們不妨一塊兒去。
You might as well phone the customer service department about it. 你不妨給客戶服務部打個電話談談這事。
Shall we walk?——We might as well. 咱們步行去嗎?——不妨走走吧。
must主要有下面用法:
1) 表示“必須”、“一定要”、“得…”(多指現(xiàn)在或將來情況):
You must cut down on smoking. 你必須少抽些煙。
Passengers must cross the line by the footbridge. 旅客必須由天橋穿越鐵路。
I must remember to go to the bank today. 我今天一定要記住去銀行。
Must we finish the exercise today? "Yes, you must. (No, you don't have to.)" “我們今天必須做完這項練習嗎?”“是的,必須做完(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. 這工作周末必須完成。
Δ否定形式表示“不得”、“一定不要”:
You mustn't take photographs in here. It's forbidden. 此處不得拍照,這是禁止的。
Cars must not park in front of the entrance. 大門前不得停車。
We mustn't be late, must we? 我們不得遲到,對吧?
You mustn't drive without a license. 你不得無照駕車。
Δ表示過去情況用had to更清楚一些,雖然must也可以表示過去情況:
I had to go to see the dentist. 我得去看牙醫(yī)。
When did you have to leave? 你什么時候得動身?
She asked him if she must (had to) work overtime. 她問他她是否一定要加班。
2) 表示推想,可譯作“一定”、“準是”等:
You must be hungry. Have something to eat. 你一定餓了,吃點東西吧。
They must be twins. 他們一定是雙胞胎。
The police are stopping all cars. They must be looking for the escaped prisoner. 警察讓所有的車都停下來,他們準是在搜尋逃犯。
There's a lot of noise from next door. They must be having a party. 隔壁那屋很嘈雜,他們準是在開晚會。
I can't find my cheque book. I must have left it at home. 我找不到我的支票本,準是留在家里了。
We must have read the same report. 我們一定是看了同一份報告。
You must have been thinking of something. 你準是在想什么心事。
3) 表示“應當(做某事)”(和should, ought的意思差不多):
You really must see that film. It's wonderful. 你真應該去看這部電影,非常精彩。
You must see what the authorities have to say. 你應當去了解一下當局怎么說。
We must think of this matter very seriously. 我們應當認認真真地考慮此事。
You must recognize that we can't allow such behaviour. 你應當明白我們不容許這種行為。
ought總是和to一道用,表示:
1) 應該,應當(意思接近于should):
I ought to write to him today. 我今天應當給他寫信。
You ought to read this book. It's marvellous! 這本書你應當看看,真是好極了。
What ought I to say to him? 我該對他說什么呢?
You ought to visit your parents more often. 你應當更多地探望你的父母。
You oughtn't to make private phone calls in work time. 在工作時間你不應該打私人電話。
I knew I ought to write to her. 我知道我應當給她寫信。
Ought I to write to say thank you? 我是不是該寫信去致謝?
Δ 后面的不定式可用完成、進行或被動形式:
They ought to have stopped at the traffic lights. 在紅綠燈前他們本應停車。
You ought to have come to the meeting. 你是應該來開會的。
We ought to be leaving now. 我們現(xiàn)在該走了。
He oughtn't to have been driving so fast. 他是不應當把車開這么快的。
He ought to be isolated. 他應當被隔離。
Something ought to be done about it. 對此應當想些辦法。
2) 表示揣測:
She ought to pass her test. 她應當能通過測試。
He ought to be there (to have arrived) by now. 他現(xiàn)在應該已經到了。
The water ought to have boiled by now. 現(xiàn)在水應該開了。
We ought to be hearing from Wendy soon. 我們不久就應可以收到溫迪的信。