情 态 动 词 用 法 分 析
当我们涉及与别人相关的事时，表达我们说话者的语气、情感和态度时，往往 使用情态助动词。 Step one. 1.Can/Could 1) 表示天生的或学到的能力“能够” eg Can you run 1,500 meters in 5 minutes? 2)表示推测可能性“可能”（否定句或疑问句） eg Can the news be t
rue? He can’t be so careless. He can’t/couldn’t have seen me yesterday because I wasn’t there. 3) 表示偶然发生的可能性“可能”（理论上的可能性） eg It can be dangerous to climb high on the tree. The climate of East China can be very cold in winter. / Don’t leave small things on the floor or table which a baby can put in its mouth. 4) 在口语中表示请求“可以” eg Can/Could you help me? The children asked if they could go for a swim. 5) 在口语中表示许可“可以” eg You can/may have a rest now. Could 比 can 口气更婉转 could /was able to 的区别 1).He could (was able to)write poems when he was only ten 表示主语某种知识或技能, 能够做某事时 could 等于 was able to 2). He was able to pass the exam because he worked hard. 表示在具体的时间内成功地做了某事时， 用 was able to 2. May/Might 1) 表示请求=can eg May I have your name , please? / May we have a rest after lunch? 在回答 may 问句时,尽可能不用 may/might eg. May I use this dictionary? --Yes, please/certainly -- No, please don’t / You’d better not/I’m afraid not 2) 表示许可=can eg You may use my dictionary. He may go there by himself. 3) 表示推测可能性“可能”( 肯定句或否定句) eg My friend may not come tomorrow. There may be something wrong with you computer. ? may not / can not 的区别 eg. He may not come,I’m not sure. He can’t come because his mother was ill. 3. Must / Have to 1).表示义务，命令，或必要“必须，应当” eg We must obey the traffic rules. Cars must not be parked here. mustn’t 表示不准，禁止 eg. You mustn’t be late for class again. 对 must 的否定回答时用 needn’t eg.–Must we finish the work tomorrow? --No, you needn’t (don’t have to) 2). 表示推测可能性“必定，准是” eg This must be the book you want. Something must have happened or he would have been here. must do / must be doing/ must have done eg. You must be tired after a day’s hard work, aren’t you？ You must have finished your homework, haven’t you? You must have finished your homework last night, didn’t you? 3) .情态动词 must 表示与说话人的愿望相反，意思是“偏要” 、 “偏偏” eg. Of course，after I gave her advice， she must go and do the opposite．
Must you make so much noise？ 4. Will /Would 1). 表示请求（用于第二人称） eg Will you please clean the room every day? Will you join us in a walk? 2 ).表示意志，意愿, 决心 =be willing to do sth. eg We will work hard until we succeed. If you will wait there for a moment, I’ll tell Mr. Lee that you have arrived. I will not stop my fight against slavery until all slaves are free. ? The door won’t shut .门关不上 3). 表示习惯性，经常性，倾向性 eg Fish will die without water. He will sit for hours reading near the window. *4).表示推测“可能” eg He will have got home by now. / That will be the postman at the door. would 用法类似 5. Shall / Should shall: 1 ).用于陈述句中的第二，三人称，表示说话者的意图，允诺，警告，命令，决 心等。 eg He shall go first, whether he wants to or not. You shall get the answer right this afternoon. 2).用于一，三人称在问句中表示征求对方意见 “要不要……” eg Shall we have a rest now? Shall he come in or wait outside? ?Will he come in? 区别 Shall the goods be sent over to you at once? Should: 1.可表示义务，责任 “应该” 它可以和 ought to，be supposed to 互换使用 eg. We should make full use of time. You should have told me the news earlier. 2.可表示有较大可能实现的猜测、推论，通常译为“可能”、“总该……吧”，相当 于 be expected to eg.They should be home by now，I think. The report was written after a careful investigation,so it should be reliable. 3.可表示意外、惊喜或者在说话人看来是不可思议的。 “竟会”、“居然”。 eg. I was surprised that he should have made so many mistakes. 6 Need / Dare 1) 用于否定句，疑问句中( 情态动词) eg. The little child dare not go out alone. Need you go there tomorrow? 2） 实义动词，后加动词不定式 eg. He dares to face difficulties./The little child doesn’t dare to go out alone 7 ought to =should ? ought not to Step Two: 情态动词+动词完成式 情态动词+动词完成式即“情态动词+ have + done 分词”，表示对过去行为或 动作进行推测、评论或判断。 1. must have done 表示对过去某事的肯定猜测。 其否定或疑问形式都用 can(could) have done 来表示. eg. Since the road is wet, it must have rained last night. He can’t have missed the way. I drew him a map. 2.may / might have done 表示推测过去某事“也许”发生了. may 比 might 表示的 可能性在说话人看来稍大些。(肯定或否定) eg. I can’t find my keys. I may / might have left them at the school yesterday. ?can/could have done (?) 3. could have done #1.在肯定句型中, 往往用作委婉的批评. 本应该 能做什么 , 而没做 ; #2. 也用作猜测 (=may/might have done). #3.Can /could
have done 用于否定句或疑问句中表示一种不太肯定的推测。 eg. You could have told us earlier. / Tom could have taken the dictionary. The dictionary has disappeared. Who could have taken it? 4. ought to / should have done ?ought not to / shouldn’t have done 用于对已发生的情况表示“责备” 、 “不满”等情感，分别表示“本应该…” 和“本应该不…” 。 eg. With all the work finished, I should have gone to the party last night. You ought not to have made fun of him. He is not the one you laugh at but learn from. 5. needn’t have done 表示过去做了某事，但没有做的必要， 意为“本没必要…” eg. You needn’t have waken me up; I don’t have to go to work today. Step Three:情态动词+动词进行式 情态动词+进行式（即情态动词+ be + doing 形式） ，表示推测或评论某动作 现在是否正在进行。 eg. He must be playing basketball in the room. She may be staying at home.
语气的分类 1. 陈述语气 (表示所说的话是事实) eg. I have told you that already. 2.祈使语气 (表示所说的话是请求或命令) eg. Make yourself at home. / Don’t be late. 3. 虚拟语气 (表示所说的话只是一种主观的愿望,假想或建议) eg. I wish I could go with you, but I can’t find any time. 虚拟语气所说的是一个条件，不一定是事实，或与事实相反。 Step one: 虚拟语气在条件句中的应用 非真实条件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。 1. 同现在事实相反的假设。 句型 ： 条件从句 主句 一般过去时 should( would etc.) +动词原形 eg. If they were here, they would help you. 2. 表示于过去事实相反的假设。 句型： 条件从句 主句 过去完成时 should(would etc.) have+ 过去分词 eg. If she had worked harder, she would have succeeded. 3. 表示对将来的假想 句型： 条件从句 主句 一般过去时 should etc.+ 动词原形 were to + 不定式 would etc.+ 动词原形 should + 动词原形 eg. If you succeeded (were to succeed /should succeed), everything would be all right. 4. 混合虚拟语气 主句与从句的动作发生在不同的时间，这时主，从句谓语动词的虚拟语气形 式因时间不同而不同，这叫做混合条件句。 If you had asked him yesterday, you would know what to do now. （从句与过去事实相反， 主句与现在事实相反。 ） If it had rained last night (过去), it would be very cold today (现在). 注意： 在虚拟语气的从句中，动词'be'的过去时态一律用"were"，不用 was， 即在从 句中 be 用 were 代替。 5. 虚拟语气的倒装 虚拟条件句的从句部分如果含有 were, should, 或 had, 可将 if 省略，再把 were, should 或 had 移到从句句首，实行倒装。 eg. Were they here now, they could help us. ?If they were here now, they could help
Had you come earlier, you would have met him ?If you had come earlier, you would have met him. 但要注意，在虚拟条件状语从句中，省略连词的倒装形式的句首不能用动词 的缩略形式。如我们可说 Were I not to do., 而不能说 Weren't I to do. Step Two: 虚拟语气在其它从句中的使用 1 A) 在宾语从句中的应用 在表示命令、建议、要求等一类动词后面的从句中，如 order, suggest, propose, require, demand, request, insist, command, insist + 从句 sb. (should) do eg. I suggest that we (should) hold a meeting next week. He insisted that he (should ) be sent there. 注意： 如 suggest / insist 用于其本意"暗示、表明"/"坚持认为"时，宾语从句用 陈述语气 判断改错: （ ） You pale face suggests that you (should) be ill. ( ) Your pale face suggests that you are ill. B）在表语从句，同位语从句中的应用 在 suggestion, proposal, idea, plan, order, advice 等名词后面的表语从句、同位 语从句中要用虚拟语气，即（should）+动词原形。 eg. My idea is that we (should) get more people to attend the conference. I make a proposal that we (should) hold a meeting next week. C）在主语从句中的应用 It is +suggested, ordered, proposed, required, demanded , requested, insisted etc 从句 （ (should) do ） eg. It is suggested that we (should) hold a meeting next week. 2. 在主语从句中的使用 从句的谓语动词要用 should 加动词原形， should 可省略。 (1) It is + important, necessary, natural, strange etc +从句 eg. It is necessary that he (should) come to our meeting tomorrow. (2) It is + a pity, a shame, no wonder etc +从句 3 .用于 wish 后面的从句. 宾语从句的动词形式为：和现在事实相反，用一般过 去时；和过去事实相反，用过去完成时；和将来事实相反，用过去将来时 （would/could etc +do ） eg. I wish I were as tall as you. / He wished he hadn't said that. I wish it would rain tomorrow. if only 则表示"如果……就好了" (和 wish 用法相同) eg. If only you would listen to our advice. /If only I had not been busy last week! /If only she could marry me. if only 也可以用于虚拟条件句中。例如： eg. If only I had more money, I could buy a car. 4. It is (high) time +从句. 谓语动词要用过去式或用 should 加动词原形， 但 should 不可省略。 eg. It is time that the children went to bed. / It is high time that the children should go to bed 5. would rather /as if +从句 （和过去相反，用过去完成时；和现在/将来相反，用 一般过去时） eg. He would rather his sister left at once. He talked as if he had been there for many times. *6. “in case, lest, for fear that”可以用来引导虚拟语气。 其形式通常为： “lest (in case, for fear that) + 主语 + should + 动词原形”。 lest, for fear that 句中的 should 可以 省去， in case 句中的 should 通常不省去 eg. He took his coat with him in case it should rain. I will not make a noise for fear that I (should/ might) disturb you. Care must be taken in using this method lest overflow (should) occur 但是 in case ,lest, for fear that 后面也可以接其他形式
copyright ©right 2010-2020。