情态动词与虚拟语气讲解及练习题
情态动词与虚拟语气
四川省达州市第一中学张国龙
长征七律诗
一. 含义和特征
1. 含义: 情态动词是表示情态意义的动词, 它表示说话人的语气和情态, 它不能单独作谓语, 必须与实义动词一起构成谓语, 情态动词没有人称和数的变化。
检验检疫局英文2. 特征: ①有词义但不完整, 不能单独作谓语, 要跟实意动词或系动词的原形作谓语。②除have to外, 可适用于各种人称和数。③有些情态动词有过去式。
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二. 基本用法
学习方法与技巧1. can/ could和be able to ①can/ could表示能力, 这时could 为can 的过去时。I can climb the cliff. He can drive a car. We could sing the song when I was young. ②表示许可。You can sit here. The plane can take off now. 在疑问句中could比can委婉, 回答用can。Can/ Could I
come here tomorrow? Yes, you can. ③表示“有时候可能会”。Even an experienced teacher can make a mistake. To stay here could be better. ④表示说话人的推测、怀疑、惊异、猜测、不肯定或不耐烦等，主要用于否定句, 疑问句或感叹句中。The story can’t be true. How could you be so careless! Where can he go? ⑤cannot…too/ enough意为无论怎么…也不过分, 越…越好。You cannot be too careful. You cannot remember enough English words.⑥can和be able to都表示能力, 意思上没多大区别。can只有can和could两种形式, 而be able to则有am/ is/ are/ was/ were able to, will/ shall be able to, have/ has/ had been able to等形式。表示当过去成功地完成某一具体动作时, 通常用was/were able to来表示。这时was/were able to 相当于managed to do sth./ succeeded in doing sth., 而could只表示过去的一般能力。He was able to translate the book into English without a dictionary. The wounded man still was able to get to the village and was saved in the end. 但用于否定句中, 两者无区别。He couldn’t/ wasn’t able to play the piano when he was at school.
关于梦想的演讲稿2. may/ might ①表示询问或允许。You may stay here as long as you like. You may sit down. 在疑问句中might比may委婉。May/Might I ask you a question? Yes, you may/ can.
whereverMay/Might I u your pen? No, you may not./ No, you mustn’t.②“may+主语+动词原形”表示祝愿。May all your dreams come true!③may/ might well意为能/ 很可能，may/ might as well意为最好/ 倒不如。He may well be proud of his son. Her appearance changed so much that you might well not recognize her. You may as well stay here.④may be与maybe的区别。He may be over twenty years old. Maybe he is over twenty years old.
3. must ①表示必须，主观看法，没有时态变化。You must study hard. You must get up early. m ustn’t表示禁止做某事,意思为禁止/ 不许。We mustn’t waste our time.You mustn’t smoke here. 回答must 提问时, 否定用needn't/ don’t have to。Must I start at once ? Yes, you must. No, you needn’t. 反意疑问句用needn’t. He must hand in his homework now, needn’t he? ②have to 表示必须或不得不, 是由于某种外界或客观原因而“必须”, “不得不”做某事。have to可用于多种时态，否定形式don’t have to表示不必。You have to wash your own clothes when you are at school. Becau of no money, he has to be hungry. You don’t have to stay at home.③表示“偏偏”之意, 指令人不愉快的事情。Why must it rain on weekends? He must play the piano at such
a late hour. ④表示必然的结果。If you don’t hurry, you must miss the train. All men must die.
look out4. shall ①shall用在第一、第三人称疑问句中, 表示说话人征求对方的意见或向对方请求指示。Shall we go out for a walk? Shall I begin at once? Where shall he wait for us? ②用于第二、三人称陈述句中, 表示说话人的意愿, 有命令、警告、威胁、强制、允诺或决心等意思。They shall do as thei r teacher says. If you don’t work harder, you shall fail. He shall be punished. You shall have the book as soon as I finish it. Nothing shall stop us from doing so.③用于所有人称, 表示规章、法令、预言等, 意为“必须”。The law shall come into effect on September 1st. Each player shall wear a number.
5. should / ought to ①表示义务, 责任, 命令或劝告等, 意为“应该”。You should be more patient. You should do better next time. We ought to help each other.在疑问句中表示建议。Should we wait? Should we start at once? Ought I to go? Yes, you ought(to). ②提出意见或请求, 意为“想, 倒想”。I should think so. I should advi you to say less and do more.③表示惊讶, 难以相信或不应该的事。Should she do such a thing? How should I kn
去世英语ow? ④ought to 表示表示义务, 责任, 命令或劝告等, 语气比should强。否定形式为oughtn’t to/ ought not to, 对一般
疑问句的回答用ought(to). 反意疑问句的附加部分用oughtn’t/ shouldn’t。You oughtn’t to lie in bed. I ought to hand in my homework now, oughtn’t I?
6. will ①用于各种人称表示意志、意愿或决心等Do what you will. If you’ll help me, I will go with you. I will never do such a thing again.②用于主语是第二人称you的疑问句中, 表示邀请, 请求或询问。Will you give me a piece of paper? Will you plea tell her the news when you e her? ③表示经常性、习惯性、倾向性等, 意为“经常、总是”。Mary will read for hours at a time. Fish will die out of water. The door won’t open.④表示命令(说话者确信命令一定会得到执行)或允诺。You will do as I say at once. You will report the accident to me afterwards. They will get enough money from me. ⑤表示能力或功能。The tree will live for three months without water. The bottle will hold a pint of milk.⑥用于祈使句的附加疑问句中。Have a cup of tea, won’t you? Give me a hand, will you? Be quiet, can’t you? Don’t forget it, will you? Don’t talk any more, will you?
7. would ①用于各种人称表示意志、意愿或决心等,是will的过去式。She said she would take care of the baby. 可用于下列词组中, would rather, would like/ love, would prefer. ②用于主语是第二人称you的疑问句中, 表示邀请, 请求或询问, 语气比will委婉。Would you tell me the way to the airport? ③表示过去经常性、习惯性、倾向性等, 意为“经常、总是”。When I was a child, I would go swimming with other children in summer. ④用于祈使句的附加疑问句中, 语气比will委婉。Clo the window, would you?
8. need 作“必须, 需要”讲, 既可作情态动词, 也可作实义动词。①作情态动词, 通常用在否定句或疑问句中, 没有人称、数、时态的变化。He needn’t pay the money. Need we do it again? Yes, you must/ have to. No, you needn’t/ don’t have to.②作实义动词时,有人称、数或时态的变化, 其变化与一般动词相同, 后面要跟带to的动词形式。He needs to think it over. We need to have a rest. They didn’t need to arrive early. The garden needs watering/ to be watered.
9. dare 作“敢”讲, 既可作情态动词, 也可作实义动词。①作情态动词, 通常用于否定句, 疑问句或条件状语从句中, 没有人称、数的变化, 但有过去式dared。She dare not go out alone.
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Dare she go out alone? Yes, she dare. No, she daren’t. He dared not talk with a stranger.②作实义动词, 有人称、数或时态的变化, 其变化与一般动词相同, 后面要跟带to的动词形式, 但在否定句或疑问句中to可以省略。He dares to face the danger. She doesn’t da re (to) ask a question. He didn’t d are (to) disobey. Do you dare (to) enter that cave alone? Does she dare (to) speak before a big audience?
