语法专练-情态动词(用Web版式打开).doc

语法专练-情态动词情态动词的用法(一)情态动词分为三种情况：1.只用作情态动词的有 must, can/could, may/might, ought to, be able to2.既可作情态动词又可作实义动词的有need, dare，have/had to, used to；3.既可作情态动词又可作助动词的有shall/should/will/would。情态动词不能单独作谓语，需要和动词（行为动词或系动词）连用，构成谓语。一、情态动词的基本用法1.can和could的用法1）表示能力或客观可能性，还可以表示请求和允许。如：Man cannot live without air.人没有空气不能活。2）表示惊异、怀疑、不相信的态度（主要用在否定句、疑问句或惊叹句中）。如：Can this be true? 这能是真的吗？2.may和might的用法1）表示许可。在表示请求、允许时，might比may语气更委婉一些，否定回答时要用mustnt，表示“不可以，禁止、阻止”之意。如：Might I use your pen?我能用你的钢笔吗？No,you mustnt.不，你不允许。2）用于祈使句中表示祝愿。如：May you succeed! 祝你成功！3.must和have to的用法1）表示必须、必要。回答must引出的问句时，如果是否定的回答，不能用mustnt，而要用neednt或dont have to。如：Must we hand in our English exercise books?我们必须交英语作业吗？Yes,you must.（No,you dont have to.）是的，你必须要交。（不，你不必）。2）have to的含义与must相似，两者往往可以互换使用，但must与have to有下列几点不同：must表示的是说话人的主观看法，而have to则往往强调客观需要。must只有一种形式，have则涉及人称、时态等方面的变化形式。二者的否定意义不大相同。如：You mustnt go.（带有很强的语气，表示“禁止、不允许”）你不许走。You dont have to go.（表示“不必”）你不必走。询问对方的意见时应用must。如：Must I clean all the room?我必须清洁房间吗？4.shall和should的用法1）shall用于第一人称，表示征求对方的意愿。如：What shall we do this evening?今晚我们要做什么？2）shall 用于第二、第三人称陈述句中，表示说话人给对方的命令、警告、允诺或威胁。如要反映客观情况或涉及法律、义务和规定时一般用ought to。在疑问句中，通常用should代替ought to。如：You shall fail if you dont work harder.（警告）如果你不努力点，你就会失败。5.will和would的用法1）表示请求、建议等，would比will委婉客气。如：Would you pass me the book? 能把这本书递给我吗?2）表示意志、愿望、决心、料想或猜想。如：I hope I would fly in the sky.我希望我能在天空飞翔。3）用“will be”和“will + have + 过去分词”的结构表示推测，主要用于第二、三人称。前者表示对目前情况的推测，后者表示对已经完成的动作或事态的推测。如：He will have arrived by now.目前他应该已经到了。4）would可表示过去反复发生的动作或某种倾向。would表示“过去习惯”时比used to正式，并没有“现已无此习惯”的含义，带would的句子不宜用在故事开头。如：During the vacation he would visit me every week.在假期的时候，他每周都来看我。注意：情态动词用于疑问句进行回答时，出现了异化现象，此时回答在某个角度不能继续使用该情态动词，而改用别的动词。见下表：疑问句式 肯定回答 否定回答Can/Could you do sth.? Yes,I/we can/could. No,I/we cant/couldnt.May I do sth.? Yes,you may. No,you mustnt/may notMust I/we do sth.? Yes,you must. No,you neednt/dont have to.Need I do sth.? Yes,you must. No,you neednt/dont have to.Will/Would you do sth.? Sure./Certainly./Yes,of course. Sorry ,but./Im afraid I cant.Shall we/I/he/they do sth.? Yes ,please./Go ahead. Youd better not .Sorry ,but.Ought you to.? Yes,you should. No,you shouldnt.二、比较can, could, may, might, must表示判断的用法从上述讲解中我们可以看到很多情态动词都可以用来表示可能性或一种推断。1.must用于肯定判断，后跟动词原形表示对于现在情况的肯定判断；而结构“must +be + doing”表示“想必正在做某事”。如：Where is Mr Li now? 李老师在哪儿？He must be working in his class,I think.我想他一定正在班里。2.may/might后跟动词原形表示对于现在情况的可能性推断。如：Im not sure whether he will come today. He may/might be ill today.我不确定是否他今天会来，他可能生病了。3.can/could用于否定句或疑问句，后跟动词原形表示对于现在或当时情况的否定或疑问性推测。如：Tom has gone to Beijing, so you cant see him in our school now.汤姆去了北京，所以你肯定不能在我们学校看见他。4.can表示一般性的、理论上存在的可能，而might则表示正在发生或将要发生的具体可能性。A wise man can sometimes make a mistake.聪明人有时也会犯错误。I might go to Beijing by air next week.下星期我可能乘飞机去北京。5.cant 表示不可能，而may not表示可能不。He cant be only fifteen.他不可能只有15岁。（可能16、17、18岁）He may not be only fifteen.他可能不止15岁。（可能15岁，也可能16岁）情态动词表示猜测时语气从强到弱的顺序是: must, will, would, ought to, should, can, may, could, might.情态动词小练（一）1. _ it be Li Ping who broke the glass?No. It _ be Wu Dong who did it. A. Can; must B. Must; need C. May; must D. Need; can 2. Dont forget to visit me when you come to Beijing._. A. I dont B. I wont C. I cant D. I havent3. Could I use your bike?Yes, surely you _. A. might B. will C. can D. should4. Her brother _ be at home now, because he was seen playing basketball in the stadium just now. A. mustnt B. neednt C. cant D. shouldnt5. When can you get my car repaired? I need it tomorrow morning. It _ be ready by 8:00. A. can B. need C. might D. should 6. Are you coming for dinner?Im not quite sure. I _ go to my uncles instead. A. must B. would C. should D. might7. Dont believe him. What he said _ be true. A. mustnt B. neednt C. shouldnt D. may not8. _ I go home now, sir?No, you _. You should finish the composition first. A. Might; wouldnt B. May; had better not C. Must; mustnt D. Need; mustnt9. _ he use your bike?Certainly. Here is the key. A. Shall B. Must C. Will D. Does10. I thought you _ like something to read, so I have brought you some books. A. may B. might C. could D. mustKey : 1-5 ABCCD 6-10 DDBAB情态动词（二）ought to的用法ought没有时态和人称的变化，后面须跟带to的不定式。其具体用法如下：1）用于第一人称，表示有责任或有必要去做某事，与should相比，语气较弱。如：We ought to be more careful with our homework.我们应当更加认真地做作业。2）用于第二、三人称，表示建议或劝告。如：You ought to follow Mr Wangs advice.你应当听王老师的话。3）表示对现在或将来某种可能性的推测，这种推测是可信的。如：Henry ought to be here soon. He left home at six.亨利应当是很快就到，他六点就从家里出来了。4）后接动词不定式完成式，表示对过去存在的某种可能性的推测，或指过去该做而未做的事情，意思是“早应该，本应该”。若是否定句，则表示发生了不该发生的事。如：Im sorry.I ought to have phoned to tell you I was coming.对不起，我本应该先给你打个电话告诉你我要来。5）ought to后可接不定式进行时，表示“应该在（立即）”，这样用时语气比should严肃。如：You oughtnt to be talking so much. 你不应当说这么多话。6）用来表达客观上难以实现或不能实现的愿望，与虚拟语气相似。如： I love summer! It ought to be summer all the year.我喜欢夏天，全年都应是夏天。情态动词+have+过去分词 “情态动词+have done ”表示推测、后悔、遗憾、责备等语气。也是语法热点之一，下面我们就来逐个击破它。1)may(might)have+donesth /can(could)have+donesth表示过去，推测过去时间里可能发生的事情。Philipmay(might)havebeenhurtseriouslyinthecaraccident.Philipcan(could)havebeenhurtseriouslyinthecaraccident.在疑问句中can/could表示对过去情况的疑问性推测，表示“可能已经了吗？”。如：Someone must have broken into our bedroom. Who could have done it?有人闯入了我的卧室。会是谁呢？Where was your sister then? 当时你姐姐在哪？She could have gone swimming with some friends.她可能和一些朋友游泳去了。2)cant / couldnt have done：表示对过去情况的否定性推测，表示“不可能已经做了某事”。如：I cant/couldnt have lost the key. I never drop things.我不可能把钥匙丢了。我从来没丢过东西。3)could + have done：表示本来能够做却没有做某事，是说话人责备的语气。 might + have done也可表示某一事情在过去没有实现并含有“劝告、责备”的意思。如：Oh,the train has left. You could have got up earlier.噢，火车已经开了。你本来可以早点起床啊。4)musthave+donesth，对过去时间里可能发生的事情的推测，语气较强，具有肯定，想必的意思。-Lindahasgonetowork,butherbicycleisstillhere.-Shemusthavegonebybus.I must have seen you somewhere, but I cant recollect your name.我一定在什么地方见过你，可是我想不起你的名字了。5)oughttohavedonesth / shouldhavedonesth本应该做某事，而事实上并没有做。Yououghtto(should)havebeenmorecarefulinthisexperiment.shouldnt/oughtnt to + have done：否定句表示过去不该做某事却已经做了的情况，也表示说话人后悔或责备的语气。如：Heoughtnottohavethrowntheoldclothesaway.（事实上已扔了。）oughtto在语气上比should要强。You shouldnt have thrown all the books.你不该扔了全部的书。6)neednthavedonesth本没必要做某事 You neednt have apologized to her. It was not your fault.你本不必向她道歉，那不是你的错。Idressedverywarmlyforthetrip,butI neednthavedoneso.Theweatherwashot.7)wouldliketohavedonesth本打算做某事I would rather have come to help you with your English, but I was too busy at that time. 我本想来帮你学英语的，但是我当时太忙了。Iwouldliketohavereadthearticle,butIwasverybusythen.8) would rather have done：表示本来想做某事却未做成的意思。如：I would rather have come to help you with your English, but I was too busy at that time. 我本想来帮你学英语的，但是我当时太忙了。9) need和dare这两个词既可以作情态动词也可以作行为动词，其用法区别如下：比较内容 是否有人称和数的变化 是否有时态的变化 是否借助于助动词搭配 行为动词 有 有 是 + to do sth./sth. 情态动词小练（二）1. I lived with my sister this summer and didnt have to pay rent. So I _ save most of my salary. A. was able to B. would C. must D. should2. I promised to get there before 5 oclock, but now the traffic is still so heavy. They _ for me impatiently. A. may wait B. must be waiting C. could wait D. ought to wait3. I _ her, but I never could. A. ought to help B. must help C. must have helped D. ought to have helped