情态动词
一、 考点、热点回顾
【词汇辨析】
1. sometimes/ some times/sometime/ some time:
sometimes: “有时”=at times. He is sometimes late for school. some times: “几次” I have been to Nanjing some times. sometime: “某一时刻” I bought it sometime last spring.
We’ll meet again sometime next week.
some time: “一段时间” We have to stay here for some time. 2. many/ much/ a few/ a little/ few/ little
(1)many修饰可数名词,much修饰不可数名词;都表示许多。例如:
许多书 许多牛奶
(2)a few和a little都表示\有一点儿\,侧重于肯定,相当于\,但a few修饰可数名词,
a little修饰不可数名词,例如: He has a few friends in London. ---Would you like some coffee? ---Yes, just a little.
(3)few和little表示\几乎没有\,侧重否定。few后接可数名词,little后接不可数名词。例如:He is a strange man. He has few words. Hurry up, there is little time left.
【固定搭配】加-ing
be busy doing sth. 忙于做…… eg: Mother is busy cooking.
look forward to + doing sth. 期待做…… eg: Tom looks forward to seeing his father again. Thank you for (doing) sth. 为了…感谢你 eg: Thank you for your help.
have fun doing sth愉快地做某事 eg: I had great fun playing in the water. =have a good time doing sth eg: I had a good time playing in the water. have problem/trouble/difficulty (in)doing sth.做某事有困难 eg: I have difficulty finishing my homework in 2 hours.
【情态动词】 又叫情态助动词。它们具有以下特点:
⑴ 它们必须与其他动词连用,即:情态动词+动词原形
表示说话人对所述动作的看法,如需要、可能、意愿或怀疑等。 ⑵ 绝大多数情态动词没有人称和数的变化,即第三人称单数不加-s (以be和have 开头的情态动词短语除外)。 ⑶ 在意义上,情态动词具有“多义性”。
例:can既可表示能力,又可表示可能、允许等意义。
【情态动词的基本用法】
1. can的基本用法:
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⑴ 表示体力或智力上的能力,即“能够,会”,可与be able to转换。 例:He can speak English. = He is able to speak English. —Can you play basketball? — No, I can’t.
如果表示将来具备的能力,要用will be able to。 例:If I have a good sleep, I will be able to do the problem. ⑵ 表示许可,主要用于口语,书面语一般用may。 例:—Can we go home now, please? — No, you can’t.
You can only smoke in this room.
You can’t keep the library books for more than a month.
⑶ 表示“可能”,与may同义,但一般用在疑问句中。 例:What can he possibly want?
在否定句中,否定形式can’t表示推测“不大可能”。 例:Anybody can make mistakes.
The news can’t be true.
与第一、二人称连用时,还可以就可能的解决问题的方式或可能的行为提出建议。在这里,也可用could使语气婉转。
例:Can / Could we meet again next week? 下周我们可以再见面吗?
—What shall we do? 我们怎么办呢?
— We can / could try asking Lucy for help. ——我们可以请露茜帮忙试试看。 You can / could help me with the cooking. 你可以帮我做饭。
2. may的基本用法:
⑴ 表示“许可”,用can比较口语化。
例:You may / can come if you wish. 如果你想来,你就来。
You may not pick flowers in this park. 本公园内不许摘花。
(may not表示按规定不许可,如果用mustn’t则表示说话人不许可。) —May I smoke here? 我可以在这里抽烟吗?
—No, you mustn’t. 不行。(mustn’t表示明确的禁止。) ⑵ 肯定句中表示推测,“可能”。
例:It may rain tomorrow. 明天可能会下雨。
The news may not be true. 这个消息可能不会是真的。 注意:如果在疑问句中表示“可能”,通常用can。 例:Can it be true? 那会是真的吗?
Who can he be? 他究竟是谁呢? ⑶ 【注意】:—May I/we……?
—Yes, you may./—No, you mustn’t. 3. must的基本用法:
⑴ 表示必须,强调说话人的主观意志。 例:I must go now, or I’ll be late.
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You must be here by ten o’clock.
【注意】:表示“必须“时,must的否定式为needn’t ,或don’t have to ,而不是mustn’t。
也就是:—Must I/we do it now?
—Yes, you must .
—No, you needn’t /don’t have to . 例:—Must I go with them?
—No, you .
⑵ 表示推测,一般只用于肯定陈述句,表示非常肯定。
例:She didn’t look at me. She must be angry. 她不朝我看,一定是生气了。
He is good at English. He must know the word. 他英语好,准知道这个词。 You must be Mr. Jones. 想必您就是琼斯先生吧。
4. have to的基本用法:
have to可视为情态动词,但它与其他情态动词在用法上稍有不同。其他情态动词没有人称和数的变化,而have to却有人称和数的变化,要视主语的不同而变化。 例:I / You / We / They have to….
He / She / It has to…. You don’t have to…. Does she have to…?
have to =have got to,意思是“必须,不得不”。 和must不同之处:must强调主观需要
have to强调客观需要。
例:Sorry, I have to leave now. 对不起,现在我得走了。
I’ve got to go to a meeting. 我得去参加一个会议。
Will he have to work deep into the night? 他将不得不工作到深夜吗? 5. need的基本用法:
need的基本词义是“需要”,它既可作情态动词,又可作实义动词。
⑴ need用作情态动词时,只用于否定句和疑问句。它只有一种形式,后接动词原形。 例:I don’t believe you need worry. 我相信你没有必要焦急。
—Need we go so soon? 我们需要这么早就去吗?
— Yes, we must. / No, we needn’t. 是的,必须。/不,不必。 So I needn’t tell him, need I? 所以我不需要告诉他,对吧? 请比较以下两句话的不同意思:
You needn’t buy the coat. 你没有必要买那件外衣。(你还没买)
You needn’t have bought the coat. 你没有必要买这件外衣的。(而你却买了) 【注意】:—Need I/we……?
—Yes,you must ./—No, you needn’t / don’t have to . ⑵ need用作实义动词时,有时态、人称和数的变化。
如果人作主语,一般后接带to的动词不定式。即need to do sth; 如果物作主语,一般后用need to be done 或need doing sth。 例如:I need to look up this word in the dictionary.
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My watch needs mending/to be mended. 我的手表需要修理了。 We don’t need to work today. (= We needn’t work today.) Does he need to go right now? (= Need he go right now?)
6. had better的基本用法:
had better常略作’d better。现代语法认为它是一个助动词,因为它后接不带to的动词不定式。 had better do sth意思是“最好做某事;还是做某事比较好”。 例:You’d better get some sleep. 你最好睡一会儿。
You’d better not do that again. 你最好别再做那件事。 What had we better do now? 我们现在怎么做才好呢? Hadn’t we better tell her the truth? 我们是否最好不告诉她真相? 【注意】:You’d better….表示劝告或委婉的命令,对长辈不宜使用。 7. could, should, would, might表示推测:
①. must多用于肯定句中表示把握性极大的推测,意思为“一定、肯定”。
如: You have worked hard all day. You must be tired. 你已辛苦工作一整天了,一定累了。 The book must be his. His name is on the cover. 这本书一定是他的,封面上写着他的名字。 【注意】 must不表推测时,在肯定句中意思为“必须(强调内在的职责)”,在否定句中意思为“不许、禁止”,以它开头的疑问句否定回答常用needn’t或don’t (doesn’t) have to。 如:We must obey the traffic rules. 我们必须遵守交通规则。 Cars mustn’t be parked here. 此处严禁停车。
—Must we hand in the papers this week? 我们必须本星期交论文吗? —No, you needn’t. 不,你们不必(本星期交)。
②. can / could多用于否定句、疑问句或感叹句中表示推测、怀疑,两者在时间上没有差别。用can时不相信的程度更强一些, can’t常常译为“不可能”。
如:The man under the tree can’t be Tom. He’s gone to England. 这个人不可能是Tom,他已经去英国了。 Can it be true that he was fooled by a five-year-old boy? 他被一个五岁的孩子愚弄了,这能是真的吗? Could this be an excuse? 这会不会是个借口? How can you be so careless! 你怎么这样粗心!
③.may / might多用来表示把握性不大的推测,意思为“也许、可能”, might比may的把握性更小一些。
may not在否定句中常常译为“可能不”。(注意区分“不可能”与“可能不”在把握性大小上的差异。) 如:Mr. Wang may know Professor Li’s telephone number.王先生也许知道李教授的电话号码。 This might be the key Tom has been looking for.这可能就是汤姆一直在找的钥匙。 She may not be there today. 今天她可能不在那儿。
二、 典型例题 【中考链接】
( )1.—Who is the man over there? Is it Mr. Li?
— No, it ______ be him. Mr. Li is much taller.
A. mustn’t B. may no C. can’t D. needn’t ( )2.—Must I go with them tomorrow?
— No,you ______.
A. mustn't B. shouldn't C. needn't D. can't
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( )3.—______ I take some photos in the hall?
— No, you ______.
A. Can, needn’t B. Must, mustn’t C. Could, won’t D. May, mustn’t ( )4.—Dad, must I finish my homework today?
—No, you ________. You may do it tomorrow.
A. needn’t B. mustn’t C. don’t D. won’t ( )5.—The lake is said to be dry. Is that true? —It _______.Look, some kids are swimming in it.
A. must be true
B. can’t be true C. may not be true
( )6.—What is your mother going to do this Saturday? —I’m not sure. She _____ go to see my grandmother. A. can
B. must
C. may
( )7.—Susan has bought a large house with a swimming pool.
—It ______ be very expensive. I never even dream about it.
A. must B. might C. can’t D. shouldn’t ( )8.—Listen! Is Professor Johnson giving a report in the hall? —No, it be him. He has gone to Japan. A. needn’t B. may not C. mustn’t D. can’t
( )9.—Let’s go to the West Hill Park by taxi.
—Oh, it is not far away from here. We _______take a taxi.
A. couldn’t B. mustn’t C. needn’t D. can’t ( )10.—Can you play the piano?
—Yes, I _______. I often practice it on weekends.
A. needn’t B. need C. can’t D. can
三、课后练习
一、用can, may, must, need, have to, had better的适当形式填空:
1. You ________________ return the library book on time.
2. I ______________ (not) find the way to the hospital. _______________ you show me the way? 3. —________________ I finish the work right now?
— No, you ________________ (not). You ____________ do it later. 4. He said he ________________ (not) come tonight.
5. Her mother was ill. She ________________ stay at home and look after her.
6. It’s time for class. You ________________ stop playing football or you __________be late for class.7. We ________________ start right now, or they would get there first. 8. The cloud is lifting, so it ________________ (not) be a rainy day tomorrow. 二、选择填空
( )1.—Do we have to finish our homework this afternoon?
—Yes, you ________. A. must B. can
C. may D. need
( )2. —Must I be in hospital for a week, Doctor?
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