分析情态动词和助动词的区别.doc

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1、 情态动词是一种本身有一定的词义,但要与普通动词一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度与看法，认为其可能、应该或必要等。 情态动词后面加动词原形。分类： 情态动词有四类： 只做情态动词：must,can(could),may(might),ought to 可做情态动词又可做实义动词：need,dare 可做情态动词又可做助动词：shall(should),will(would) 具有情态动词特征：have(had) to,used to位置: 情态动词在句中放在谓语动词之前, 谓语动词前假设有助动词,那么在助动词之前,疑问句中, 情态动词那么在主语之前。 I ca

2、n see you. Come here. 我能看见你，过来吧。 He must have been away. 他一定走了。 What can I do for you 我能帮你吗？ How dare you treat us like that！ 你怎能那样对待我们！特点: 情态动词无人称与数的变化, 情态动词后面跟的动词需用原形,否认式构成是在情态动词后面加 not。 个别情态动词有现在式与过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去，现在或将来。情态动词属非及物动词，故没有被动语态。 He could be here soon. 他很快就来。 We

3、 cant carry the heavy box. 我们搬不动那箱子。 Im sorry I cant help you. 对不起，我帮不上你。 根本助动词与情态助动词最主要的区别之一是，根本助动词本身没有词义，而情态助动词那么有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想： What have you been doing since 构成完成进展体，本身无词义 I am afraid I must be going. 一定要 You may have read some account of the matter. 或许已经 除此之外，情态助动词还有如下词法与句法特征：

4、 1 除ought与used以外，其他情态动词后面只能接不带to的不定式。如果我们把ought to与used to看做是固定词组的话，那么，所有情态动词无一例外地只能接不带to的不定式： We used to grow beautiful roses. I asked if he would come and repair my television set. 2 情态助动词在限定动词词组总是位居第一： They need not have been punished so severely. 3 情态助动词用于第三人称单数现在时的时候，没有词形变化，即其词尾无-s形式： She dare

5、not say what she thinks. 4 情态动词没有非限定形式，即没有不定式与分词形式，也没有相应的动名词： Still, she neednt have run away. 5 情态助动词的“时的形式并不是时间区别的主要标志。在不少场合，情态助动词的现在时与过去时形式都可以表示现在、过去或将来时间： Would you mind very much if I ask you to do something She told him he ought not to have done it. 6 情态助动词之间是相互排斥的，即在一个限定动词词组中只能出现一个情态助动词，但有时却可

6、以与have与be根本助动词连用： You should have washed the wound. Well, you shouldnt be reading a novel.用法 首先它是动词，而且不同于行为动词，行为动词表示的是可以通过行为来表达的动作如写，读，跑，而情态动词只是表达的一种想法如能，也许，敢。 用法是：情态动词+行为动词原形 例句：I can read this sentence in English. 我能用英语读这句话。 情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语, 只能与其他动词原形构成谓语。 We can be ther

7、e on time tomorrow.我们明天能按时去那儿。 May I have your name 我能知道你的名字吗？ Shall we begin now我们现在就开场吗？ You must obey the school rules.你必须遵守校规。 情态动词数量不多,但用途广泛,主要有以下: can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would),have (to) ,had better. 助动词(auxiliary)主要有两类：根本助动词(primary

8、 auxiliary)与情态助动词(modal auxiliary)。根本助动词有三个：do, have与be；情态助动词有十三个：may, might; can, could; will, would; shall, should; must, need, dare, used to, ought to. 上述两类助动词的共同特征是，在协助主动词构成限定动词词组时，具有作用词的功能： 1 构成否认式： He didnt go and neither did she. The meeting might not start until 5 oclock. 2 构成疑问式或附加疑问式： Must

9、 you leave right now You have been learning French for 5 years, havent you 3 构成修辞倒装： Nowhere can he obtain any information about his sister. Hardly had he arrived when she started complaining. 4 代替限定动词词组： A: Who can solve this crossword puzzle B: Tom can. A: Shall I write to him B: Yes, do.can与could

10、的用法 1. 表示能力或客观可能性，还可以表示请求与允许。如： Can you finish this work tonight Man cannot live without air. Can I go now Yes, you can. 注意：could也可表示请求，语气委婉，主要用于疑问句，不可用于肯定句，答语应用can即could不能用于现在时态的简单答语中。如： Could I come to see you tomorrow Yes, you can. 否认答语可用No, Im afraid not. can表示能力时，还可用be able to代替。如： Ill not be a

11、ble to come this afternoon. 2. 表示惊异、疑心、不相信的态度。主要用在否认句、疑问句或惊叹句中 Can this be true How can you be so careless! This cannot be done by him. 3. “can(could) + have + 过去分词的疑问或否认形式表示对过去发生的行为疑心或不肯定。如： He cannot have been to that town. Can he have got the book 4. 用在疑问句及否认句中,表示惊讶,不相信等. 5. cannottooenough表示无论怎样

12、也不过分,越越好may与might的用法 1. 表示许可。 表示请求、允许时，might比may的语气更委婉一些，否认答复时(口语中常用) no , you cant . or , yes, please 用mustnt表示“不可以、“制止、“阻止之意(具有强烈制止的意思)如： You may drive the car. Might I use your pen No, you mustnt. 用May I . 征询对方许可在文体上比拟正式，在口气上比拟客气。在日常口语中，用Can I . 征询对方意见在现代口语中更为常见。 2. 用于祈使句中表示祝愿。如： May you succeed!

13、 3. 表示推测、可能疑问句不能用于此意。 He may be very busy now. 4. “may(might) + have + 过去分词表示对过去发生的行为的推测。如： He may not have finished the work.must与have to的用法 1. 表示必须、必要。must表示主观多一些而have to那么表示客观多一些如： You must come in time. 答复must引出的问句时，如果是否认的答复，不能用mustnt，而要用neednt或dont have to。 Must we hand in our exercise books to

14、day Yes, you must. (No, you dont have to.) 2. “must be + 表语的构造表示推测，它的否认或疑问式用can代替must。 This must be your pen. 3. “must + have + 过去分词的构造常用在肯定句中，表示对过去发生的行为的推测。它的否认或疑问式用can代替must。 He must have been to Shanghai. 4. have to的含义与must相似，两者往往可以互换使用，但have to有各种形式，随have的变化而定。must与have to有以下几点不同： must表示的是说话人的主观

15、看法，而have to那么往往强调客观需要。如： The play is not interesting. I really must go now. I had to work when I was your age. must一般只表现在，have那么有更多的时态形式。 二者的否认意义不大一样。如： You mustnt go. 你可不要去。 You dont have to go. 你不必去。 询问对方的意愿时应用must。如： Must I clean all the room 注意：have to也可拼做have got to。dare与need的用法 1. need表示“需要或“必

16、须，作情态动词时，仅用于否认句或疑问句中，在肯定句中一般用must, have to, ought to,或should代替。如： You neednt come so early. Need I finish the work today Yes, you must. 注意：neednt + 不定式的完成式“表示本来不必做某事而实际上做了某事。如： You neednt have waited for me. 2. Dare作情态动词时，主要用于疑问句、否认句与条件从句中，一般不用在肯定句中。如： How dare you say Im unfair. He darent speak Eng

17、lish before such a crowd, dare he 3. Dare与need常用作实义动词，有时态、人称与数的变化，所不同的是，作实义动词时，在肯定句中，dare后面通常接带to的不定式，在否认与疑问句中，dare后面可接带to或不带to的不定式。如： I dare to swim across this river. He does not dare (to) answer. Dont you dare (to) touch it! I wondered he dare (to) say that. He needs to finish it this evening.sha

18、ll与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 2. Shall用于第一、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示。如： Shall we begin our lesson When shall he be able to leave the hospital 3. Shall用于第二、第三人称，表示说话人给对方命令、警告、允诺或威胁。如： You shall fail if you dont work harder. 警告 He shall have the book when I f

19、inish reading. 允诺 He shall be punished. 威胁 4. Should表示劝告、建议、命令，其同义词是ought to；在疑问句中，通常用should代替ought to。如： You should go to class right away. Should I open the window Should的含义较多，用法较活，现介绍三种其特殊用法。请看下面的句子： I should think it would be better to try it again. 我倒是认为最好再试一试。 You are mistaken, I should say. 依

20、我看，你是搞错了。 I should advise you not to do that. 我倒是劝你别这样做。 This is something I should have liked to ask you. 这是我本来想问你的。 从以上例句可以看出：情态动词should用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语气。 Should还可以用在if引导的条件从句，表示一件事听起来可能性很小，但也不是完全没有可能。相当于“万一的意思。从句谓语由should加动词原形构成，主句谓语却不一定用虚拟语气。如： Ask her to ring me up if you should see

21、her. 你万一见到她，请让她给我打个 。 If you should change your mind, please let us know. 万一你改变主意，请通知我们。 Should I (If I should) be free tomorrow I will come. 万一我明天有时间，我就来。 此外，Why(or How) + should构造表示说话人对某事不能理解，感到意外、惊异等意思。意为“竟会。如： Why should you be so late today 你几天怎么来得这么晚？ Where is Betty living 贝蒂住在哪里？ How should I

22、 know 我怎么会知道呢？ I dont know why you should think that I did it. 我真不知道你凭什么认为这件事是我干的。 5. “should + have + 过去分词构造一般表示义务，表示应该做到而实际上没有做到，并包含一种埋怨、责备的口气。如： She should have finished it. I should have helped her, but I never could. You should have started earlier.will与would的用法 1. 表示请求、建议等，would比will委婉客气。如： Wo

23、uld you pass me the book 2. 表示意志、愿望与决心。如： I will never do that again. They asked if we would do that again. The door wont open 3. 用“will be与“will(would) + have + 过去分词的构造表示推测，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： This will be the book you want. He will have arrived by now. The guests would ha

24、ve arrived by that time. I thought you would have finished this by now. 4. Would可表示过去反复发生的动作或某种倾向。Would表过去习惯时比used to正式，并没有“现已无此习惯的含义。如： The wound would not heal. During the vacation he would visit me every week. 5. 表料想或猜测。如： It would be about ten when he left home. What would she be doing there I t

25、hought he would have told you all about it.ought to的用法 1. Ought to表示应该。如： You ought to take care of him. 2. 表示推测。注意与must表示推测时的区别： He must be at home by now. 断定他已到家 He ought to be home by now. 不十分肯定 This is where the oil must be. 比拟直率 This is where the oil ought to be. 比拟含蓄 3. “ought to + have + 过去分词

26、表示过去应做某事而实际未做。如： You ought to have asked him (but you didnt). 这时，ought to与should可以互相换用。 注意：在美国英语中，ought to用于否认句与疑问句时，to可以省略。如： Ought you smoke so much You oughtnt smoke so much. ought与should的区别： 1.ought语气略强。 2.should较常用。 3.ought在美国英语中用的很少，而should却相当常用。 4.ought属正式用语。used to，had better，would rather的用法

27、 1. Used to表示过去的习惯动作或状态，现在已不存在，在间接引语中，其形式可不变。如： He told us he used to play football when he was young. 在疑问句、否认句、否认疑问句或强调句中，可有两种形式： 疑问句 Did you use to go to the same school as your brother Used you to go to the same school as your brother 否认句 I usednt to go there. I didnt use to go there. Usednt 亦可拼作

28、usent，但发音皆为ju:snt。 否认疑问句 Usent you to be interested in the theatre Didnt you use to be interested in the theatre 强调句 I certainly used to smoke, but it was a long time ago. I certainly did use to smoke, but it was a long time ago. 其反意疑问句或简单答复中，也有两种形式： She used to be very fat, didnt she 口语+常用/ use(d)n

29、t she 正式+过时 Did you use to play chess Yes, I did. Used you to get up early in the morning Yes, I did. (Yes, I used to.) 2. Had better意为“最好，后接不带to的不定式。如： We had better go now. Yes, we had (wed better / we had better). Hadnt we better stop now (Had we better not stop now) I think Id better be going. 用

30、于进展时态，表“最好立即 You had better have done that. 用于完成时态，表未完成动作 注：had best与had better同意，但较少用。You had better 用于同辈或小辈，对长辈不可用。 3. Would rather意为“宁愿，表选择，后接不带to的不定式。如： Id rather not say anything. Would you rather work on a farm Wouldnt you rather stay here No, I would not. Id rather go there. 由于would rather表选择

31、，因而后可接than。如： I would rather work on a farm than in a factory. I would rather watch TV than go to see the film. I would rather lose a dozen cherry trees than that you should tell me one lie. Id rather you didnt talk about this to anyone. 句中的d rather不是情态动词，would在此是表愿望的实义动词can (could), may (might), 用法

32、: can (could) 表示说话人能,可以,同意,准许,以及客观条件许可,could 为 can 的过去式。 Can you pass me the books 你能给我递一下书吗 Could you help me, please 请问,你能帮助我吗 What can you do 你能干点什么呢 Can you be sure 你有把握吗 can 与could 只能用于现在式与过去式两种时态,将来时态用 be able to 来表示。 He could help us at all. 他完全可以帮助我们。 With the teachers help,I shall be able t

33、o speak English correctly. 由于教师的帮助,我将能准确地讲英语。 may (might) 可以, 表示说话人同意,许可或请求对方许可。 You may take the book home. 你可以把书带回家去. May I come in 我可以进来吗 May I use your dictionary 我可以用你的词典吗 You may put on more clothes. 你可以多穿点衣服. He said he might lend us some money. 他说他可以借给我们一些钱。 may 否认式为 may not, 缩写形式是 maynt. mi

34、ght 是may 的过去式, 有两种用法, 一种表示过去式，一种表示虚拟语气, 使语气更加委婉, 客气或对可能性的疑心。 He told me he might be here on time. 他说他能按时间来。 Might I borrow some money now. 我可以借点钱吗 He might be alive. 他可能还活着。编辑本段must, need, ought to, dare (dared)用法 Must 必须,应该,一定,准是, 表示说话人认为有必要做某事, 命令, 要求别人做某事以及对事物的推测。 must 用来指一般现在时与一般将来时, 过去式可用 have

35、to 的过去式代替。 I must finish my work today. 我今天必须完成我的工作。 You mustnt work all the time. 你不能老是工作。 Must I return the book tomorrow 我必须明天还书吗 After such a long walk, you must be tired. 走了这么长的路,你一定困了。 He must be the man I am looking for. 他一定是我要找的人。 He had to go because of somebodys calling him that day. 那天他要走

36、是因为有人叫他。 must + have + 过去分词,表示现在对过去事物的推测。 He must have told my parents about it. 他一定把这件事情告诉我父母亲了。 He must have received my letter now. 他现在一定收到我的信了。 Its six oclock already, we must have been late again. 已经六点钟了，我们一定又迟到了。 must 与 have to 的区别: must 表示说话人的主观思想, have to 表示客观需要。 You must do it now. 你必需现在就干。

37、(说话人认为必须现在干) I have to go now. 我得走了。(客观条件必须现在走) need 需要 多用在否认式或疑问句中. Need I attend the meeting tomorrow 我需要明天参加会议吗 You need not hand in the paper this week. 这一周你不必交论文。 need 是一个情态动词, 他的用法完全与其他情态动词一样, 但 need 还可当作实义动词使用, 这时 need 就象其他动词一样,有第三人称,单复数, 后面加带 to 的动词等特性。 I need a bike to go to school. 我上学需要一辆

38、自行车。 Do you need a dictionary 你需要词典吗 She needs a necklace. 她需要一条项链。 neednt + have + 过去分词 表示过去做了没必要做的事情。 You neednt have taken it seriously. 这件事情你不必太认真。 dare 敢 多用在否认或疑问句中。 The little girl dare not speak in public. 小女孩不敢在公众面前说话。 Dare you catch the little cat 你敢抓小猫吗 dare 除用作情态动词外,更多的是当实义动词使用, 用法同实义动词一样

39、,要考虑人称,单复数,时态等。 Do you dare to walk in the dark 你敢黑夜走路吗？ He doesnt dare to tell the teacher what happened that day. 他不敢告诉教师那天发生的事。编辑本段ought，will ，Shall, should，have to ought 应当,应该 后面跟带有 to 的动词不定式。 You ought to read these books if you want to know how to repair the motorcar. 如果你想知道如何修理汽车,你应该读这些书。 You

40、 ought to bring the child here. 你应该把孩子带来。 ought + to have done 句型。指过去动作,表示一件事情该做而未做。 You ought to have been here yesterday. 你昨天就应该来。 ought not to have done 句型。表示一件不该做的事情却做了。 You ought not to have taken the book out of the reading-room. 你不应该把书带出阅览室。 will (would)决心,愿望。 would 为 will 的过去式, 可用于各人称。 Ill d

41、o my best to catch up with them. 我要尽全力赶上他们。 Ill never do it again, thats the last time. 我再不会做那件事情了,这是最后一次。 He said he would help me. 他说他会帮助我。 will, would用于疑问句表示说话人向对方提出请求或询问,用 would 比 will 更婉转,客气。 Its hot. Will you open the windows 天气太热了,你能翻开窗户吗 Will you help me to work it out 你能帮我解这道题吗 Would you li

42、ke some coffee？ 给你来点咖啡怎样？ Shall, should表示命令,警告,允诺,征求,劝告,建议惊奇。 You should hand in the exercise book. 你应该交作业本儿了。 This should be no problem. 这应该没问题。 Shall we go now. 我们现在可以走了吗 Why should I meet him？ 为什么我要见他 have to,不得不,必须,表示客观条件只能如此, 而must 那么表示主观思想必须。 I have to go now. 我现在得走了。 I have to cook for my child. 我得给孩子做饭。 You must be here on time next time. 你下次一定要按时来。 We must go to get the timetable ourselves. 我们一定要自己去拿时刻表。第 23 页