5-助动词.doc

助动词(Auxiliary verb)和情态动词(Modal verb)一 助动词助动词本身没有词义，而是用来帮助别的动词来表示时态，语态，语气等，或是帮助构成否定式或疑问式。英语中的助动词有5个：be (been, being, was, were, am, is, are)have (has, had, having)shall (should)will (would)do (does, did)助动词必须随主语的人称和数进行变化。助动词的用法be可用来：1. 构成进行时态2. 构成被动语态3. 和动词不定式构成谓语，表示： 按计划安排要发生的事或打算做的事（意思接近be going to）“要”:A new hospital is to be built in our district.They were to leave the following day. 应当（该）做的事(接近should）Nobody knew what was to be done.(没人知道该怎么办。)You are to be back before five. 能够，可以做的是（接近can, may）Such books are to be found in any library.Not a sound was to be heard. 必须或不得不做的事（接近must, need或have to）You are to move out of the house right away.These books are not to be taken out of the room. 想要做的事（接近want to, intend to, 多用于条件从句中）I must continue to learn if I am to make further progress.If we are to be there in time, well have to hurry up. 后来将发生的事（接近be destined to,多用过去时）“一定”He was to regret this decision.(这一决定他将来是会后悔的)This plan, however, was to be alerted later.另外，be 的过去时可以和不定式的完成形式构成谓语，表示“本来打算.”。I was to have seen him yesterday, but was called away to attend a meeting.(我昨天本来要和他见面的，但被叫去开会了。)He was to have returned today, but was asked to stay another week.have 可用来：1. 构成完成时态和完成进行时。2. 和动词不定式构成谓语，表示因客观环境促使不得不做的事情。The train has left. Well have to wait for the next train.As the bus was no longer running, we had to walk home.在口语中have got to也常用来表示同样的意思：Youve got to do it today.(=You have to do it today.)(你必须今天做。)You have got to be telling lies sometimes.(有时你不得不撒谎。)【注】have还可用在下面两种结构中(have为实意动词)： Please have someone take these things to her house. I wouldnt have you do that. I should like to have my hair cut this week. Where did you have the photograph taken?do可用来：1. 构成疑问式和否定式。2. 加强语气。I do think you should go.He did tell me that he would help us in the work.3. 代替前面刚出现的动词来避免重复。You dont want to lag behind(落后). Neither does she.She speaks much more fluently now than she did last term.【注】有时，在代替前面刚出现的动词时，do后面还需加一个so字:You should help him since you have promised to do so.在作表意动词时do的用法越来越活，可表示种种动作，如：Will you do the potatoes ?She has done some really good essays.Have you done the Tower?He does his guests very well.还可以表示“打扫”， “洗”，“刷”，“梳”，“学”，“翻译”，“演出”，“观看”等意思。Shall可以用来：1. 构成将来时态，单纯表示未来情况。这时它在陈述句中只用于第一人称，在问句中只用于第二人称：We shant be back tonight.Tomorrow we shall have finished the whole thing.Shall you be free tonight? (No, I shant).What shall you do next?实际上，只有部分英国人这样用，其他说英语的国家都用will。2. 用在问句中征求对方的意见和指示，这时可以用于第一人称和第三人称：Shall I turn on the light?What shall we do this evening? Shall we go to the theatre?Lets have dinner out tonight, shall we?Shall he come to see you?（你说要不要他来看你？） Will he come to see you ?（他会不会来看你？）第三人称用shall仅限于英国人。美国及其他说英语国家多避免这样用。例如上两句就可以用should代替shall。他们有的人甚至第一人称也不用shall，而用will.3. 用于陈述句中，表示允诺，警告，命令，决心，强制等，这时起情态动词作用，可用于任何人称（这种用法现在已不很普遍）：Dont worry. You shall get the answer this very afternoon.(允诺)He shall be sorry for it one day, I tell you.(警告)Nothing shall stop us from carrying out this plan.(决心)will可以用来：1. 构成将来时态，一般用于第二，三人称。You will have got to Shanghai by this time tomorrow.2. 用于疑问句，表示请求，邀请。Will you type this, please?If you want help, let me know, will you?3. 用于陈述句，表示意愿，可用于各个人称。I will never talk about that again.We will uphold the wishes of the people.(我们要尊重人民的意愿。)4. 表示某种倾向或习惯性的动作。Fish will die out of water.No matter what you may say, he will always stick to his own views.5. 表示一种猜想。This will be the house youre looking for.(这大概是你找的那个房子吧。)You will remember that we came to see you once last week.(你大概还记得我们上星期来过一次)should可以用来：1. 构成过去将来时态，作为shall的过去形式，用于第一人称。He asked me whether I should be free tonight.Did you expect that we should come so early?2. 构成合成谓语，表示“应当”做或发生的事。We shouldnt throw cold water on him.Such a thing shouldnt be allowed to happen again.3. 构成虚拟语气，用在： 条件句的主句或从句中。Let me know if you should hear more news.（万一听到更多消息请你通知我） 表示目的的状语从句中。We went over the document again and again lest we should miss any of the main points.(，唯恐忽略什么要点。) 表示建议，命令等的从句中。They moved that you should be made a member of the committee.(他们提议你担任这个委员会的委员。)It is requested that you should be present at the opening ceremony. 表示惊异，赞叹，不满等情绪的句子中。Its unfair that so many people should lose their jobs.Its wonderful that you should have achieved so much in these years. 委婉陈述自己意见的句子中。I should think you are right.This is something I should have liked to ask you.(这是我本来想问你的。)would可以用来：1. 构成过去将来时，作为“will”的过去形式，可用于各种人称。I thought you would be there.For these trips we would return on Monday morning.2. 构成虚拟语气用在：条件句的主句中（用在各人称）。If there were an accident, we would have to report it.He would have said more, had he not walked away.委婉地提出请求，建议或看法的句子中。When would it be convenient for you to come?Im afraid the journey would be too expensive.3. 表示意愿，在陈述语气和虚拟语气中都可以用。Some man would do more for a dog than they would for a wife.Id be glad if you would give me an account of it.(你如果愿意把情况给我谈谈我将很高兴。)4. 表示过去反复发生的动作。Occasionally she would come to see us.Every evening he would teach us to read and write.5. 表示过去的一种倾向。He told me the box wouldnt open.The wound would not heal.6. 表示一种揣测。That would be his mother.Peter would still be reading his paper.情态动词情态动词的特点是他有一定的词义，和另一动词构成谓语，在各种人称后面用同样的形式。除ought to外其他情态动词都跟动词原形。can could may mightmust ought need dare dared此外shall, will, should, would在一定场合下也可用作情态动词。can可以用来：1. 表示能力A blind man cannot judge colors.Two eyes can see more than one.2. 表示客观可能性A more suitable book cant be found.A cracked bell can never sound well.(破了的钟声永远不会好听。)3. 表示允许（和may很相近）Can I come in?You can go now.4. 表示惊异，怀疑，不相信等态度（这主要用在否定句疑问句或惊叹句中）How can you be so careless!What can he mean?can=be able to 在表示能力这一点上意义相同，后者能有更多时态形式。Could可以用来：1. 表示“能力”或“可能性”，作为can的过去形式。Could you follow her talk?She asked whether she could take the books out of the room.2. 表示惊异，怀疑，不相信等态度。Where could(can) they be now?How could(can) he be so conceited?(他怎么会这样高傲？)(这时could 和can是可以互换的，用could时口气较缓和，用can时不相信的程度更强些，两者时间上没有差别。）3. 比较委婉客气地提出问题或陈述看法。Could(can) you lend me your thermos?I could come earlier, if necessary.4. 在虚拟条件句中构成谓语。I would help you if I could.If you had tried harder, you could have overcome the difficulties.may可以用来：1.询问或说明一件事可不可以做。May I trouble you with a question?You may take this seat if you like.但回答这种问题是，多避免用may这个词，而用其他方式，以免显得口气太严峻或不客气，如：May I smoke here? Yes, please. Certainly. Please dont. No, you mustnt.2. 表示一件事或许会发生（或是某种情况可能会存在）。只用在陈述句中。A fool may give a wise man counsel.(傻子也可能给聪明人出主意。)You may walk ten miles without seeing a house.3. 在表示目的或让步的状语从句中构成谓语。Write to him at once so that he may know in time.Come what may, well always stand together. (不管发生什么情况，我们将永远站在一起。)May 间或也可以用来表示祝愿：May you continue in your efforts and achieve new and greater successes.(祝你们继续努力取得新的更大的胜利。)May that day come soon.Might可以用来：1. 作为may的过去形式，来表示可以做的事或可能发生的事。He thought it might be wise to try his luck there. (他想去那儿碰碰运气也不错。)She was afraid they might not like the idea.2. 代替may，表示可以做的事或可能发生的事。You might as well speak your mind.(你不妨把心里话都讲出来。比may。显得婉转)The paper says that it might rain today.3. 在表示目的等的状语从句中构成谓语。He works hard so that he might become better-off someday.He died so that the others might live.4. 在虚拟条件句的主句中构成谓语。She might have learnt more if she had made better use of her time.If he were here, you might get some help from him.must可以用来：1. 表示必须要做的事。We must do everything step by step.You mustnt talk like that.(你可不能这样说话。)【注】在回答由must引起的问题时，如果是否定的答复，不能用mustnt，而需要用neednt或dont have to，因为mustnt是“一定不要”的意思，常可译为“不能”。2. 表示一种揣测（只有在肯定句中能这样用）This must be your room.There must be a mistake.这种揣测比may表示的要肯定得多。3. 表示“偏偏”这个意思。The car must break down just when we were about to start off.(我们正要出发时偏偏车又坏了。)At a time when everybody was in bed, he must turn his radio on.（大家都上床睡了的时候他偏偏把无线电打开了。）ought可以用来：和不定式构成谓语。1. 表示应该做的事情（和should差不多，只是口气稍微重些）。We ought to help each other in our work.He said such a thing ought not to be allowed to happen.(他说这样的事不应当允许发生。)2. 表示非常可能得事。She ought to be home by now.If we start right now, it ought to be able to get there in time.【注】在头一种用法中ought to和should意思相近，但它们中间也有一些差别，在表示因责任，义务等该做的事情时，常用ought to，在表示某件事适于做时多用should，在下面的句子中这两个词就不宜换用。You are his father. You ought to take care of him. We should not use too many big words in our everyday speech. (在日常会话中我们不宜于用太多的大字。)但在很多情况下两者都可以用，只是口气不同而已。You should do as he says. (你应当照他说的做。)You ought to do as he says.（你应该照他说的做。）You shouldnt talk like that.（你不应当这样谈话。）You oughtnt to talk like that.（你不应该这样谈话。）总的来说should比ought to用的更多些。need可以用来：need可以用作情态动词，表示“需要”这个意思；主要用于否定句及疑问句。Need you go so soon?(你需要这么早走吗？)So I neednt tell him, need I?(我无需告诉他，对吧？)Thats all settled. It neednt be talked about.(已经完全解决了，不必谈了。)在有否定意思的句子（如带有no, hardly等否定的句子）中也可以用。Now there need be no arguments about this question.(现在这问题没必要争论了。)I hardly need say how much we missed you.（不用说我们多么想念你.）如果是用作及物动词，和不定式连用，就可以用于各种结构。Does he need to know it?You dont need to do it yourself.The question needs to be discussed.do(es) not need to 这个结构比较文气一些，在口语中用neednt时更多些。在个别情况下，这两种结构在意义上略有差别。如：He doesnt need to be told.(不必告诉他了。)他已经知道啦。He neednt be told.（勿需告诉他。）告诉他没好处。dare可以用来：dear有时也用作情态动词，表示“敢于”这个意思，主要用于疑问句，否定句及条件从句中。Dear you go home alone?She dear not say what she thinks.I wont allow you to swim across the river, even if you dear do it. The current is too swift.但现在用作及物动词的时候更多些，可以跟不定式，用于各种结构。The girl did not dare to go home.I have never dared to tell him about it.(我一直不敢把这事告诉他。)I wonder how he dared to say such a thing.情态动词+have+过去分词不同的情态动词组合，意思的差别很大。下面分别讲一下：1. could +have +p.p. 表示“过去可能完成但事实上并没有实现的动作。You could have done the work better.(你本来可以做得更好些。)事实做得不如理想那么好。can, could 用于否定，疑问句中could(can) +have +p.p.表示对过去发生事件的“怀疑”或“不肯定”Could较can更加表示说话人的“不肯定”的语气。Can he have left already?Could she have forgotten my address?（他会把我的地址忘了吗？）Surely they cannot have heard the news.（他们决不会听到这个消息吧。2. might(may) +have +p.p.表示对过去的推测，认为某一事情在过去“可能”发生。这里may和might 都指过去，不过might 较为含蓄委婉或更加不肯定。He may(might) not have seen the film.The monitor may(might) have gone to the library.【注】may和