情态动词全解析一、何谓“情态动词”？情态动词主要用来表示说话人的情感、态度等，是中学英语语法的重点，也是高考的热点，是单项填空必考的一个知识点。
情态动词在近五年高考中主要考查四点：情态动词表示推测和可能性的用法；情态动词与虚拟语气；情态动词的表达“情感、态度、语气等”，情态动词表示“必要性”等方面的用法。
二、情态动词的特点1.没有人称和数的变化。
2. 有些情态动词有过去式的变化:. will → would , can → could , may→ might , dare → dared三、情态动词的否定形式情态动词+ not +动词原形can not: can't , must not: mustn't , need not : needn't四、情态动词的用法及相互间的区别（注意：这是常考的考点）1. can , be able to be able to 表示经过努力后, 能够做到; be able to 有多种形式的变化。
can1). 表示体力或脑力方面的能力;2). 表示允许、可能性。
could 是can的过去式, 表示过去有能力及过去存在的可能性 ; 用于疑问句表示委婉地提出问题。
1) The fire spread through the hotel very quickly but everyone ____ get out.A. had toB. wouldC. couldD. was able to2) -Will you stay for lunch?-Sorry, __. My brother is coming to see me.A. I mustn'tB. I can'tC. I needn'tD. I won't表示询问或说明一件事可不可做; 表示某事有可能发生。
might是may的过去式; 用在疑问中比may委婉、客气。
1) -May I take this book out of the reading-room?-No, you mustn't. ( Yes, you may.)2) -Might I make a suggestion? -Yes, you may.3. must1). 表示必须要做的事: 必须2) 表示很有把握的推断: 一定, 准是。
have (has)to : have (has)got to 必须, 不得不。
过去式: had to3) -Must I get to the station before three o'clock?-Yes, you must. ( No, you needn't. )4) I'm afraid you will have to wait a while.5) She must be in the classroom now.6) Mary ____ be in Paris, I saw her in town only a few minutes ago.A. mustn'tB. shouldn'tC. can'tD. may not4. shall1) 在疑问句中, 用于第一、三人称表示说话人征求对方的意见或向对方请求。
2) 用于二、三人称,表示说话人给对方的命令、警告、允诺等概念。
1) - Shall I place an order with you now? -No, you needn’t.-Shall he turn down the radio a bit? -Yes, please.(No, please don't.)2) You shall have the English book as soon as I finish it.3) Everything that he owns shall be taken away from him.4) Your brother seldom comes to see you, ____?A. does heB. doesn't heC. will heD. isn't he5) It's a fine day. Let's go fishing, ____?A. won't weB. will weC. don't weD. shall we5. should 应该 ; 应当1) You should listen to the doctor's advice.2) You should study the article carefully.6. will, would1) 在疑问句中用于第二人称,表示说话人向对方提出请求或询问。
用would语气更加婉转。
2) will 表示现在的习惯性动作或状态; would 表示过去的习惯性动作或状态。
3) will 用于各种人称, 表示意志、意愿、决心、允诺; would 表示过去时间的意志、意愿、......。
(1) Don't smoke in the meeting room, ___ you?A. do youB. will youC. can youD. could you-Will you come with me? -Yes, I will.(I am sorry , I can't.)(2) -Would you tell us something about yourself? -Yes, I will.(3) - It's my birthday tomorrow. Don't forget to come to my party.- _____ .A. I don'tB. I won'tC. I can'tD. I haven't7. ought to 应该; 应当1) You oughtn't to smoke too much.2) She ____ for what she has done.A. ought to praiseB. ought be praisedC. ought to have praisedD. ought to be praised8. dare 1. dare to come 2. dare come1) He dare not tell the truth.2) He doesn't dare to come out at night.3) I don't know whether he ____ try.A. dareB. needsC. wantsD. is allowed9. need1). 作为情态动词:必须2). 作为实义动词: 需要A.主语是人 need( to do something ; to be done by somebody)B. 主语是事物 need ( doing; to be done)1) -Do they need to take any books with them?-No, they don't need to.2) -Need we buy any new equipment? -No, we needn't.3) This farm tool needs repairing.This farm tool needs to be repaired.4) -Shall I tell John about it ?- No, you ___ . I've told him already.A. needn'tB. wouldn'tC. mustn'tD. shouldn't5) It's a fine day. You ____ take a raincoat with you.A. can'tB. mustn'tC. needn'tD. may not[★★★]五、情态动词的解题例析(1) 认真审题，结合所给出的语境，正确把握说话者的语气、情感、态度、观点等。
(2) 认真思考所给选项中情态动词的基本特征和用法，并结合语境推敲答案。
(3) 要注意把握时间概念。
情态动词无论是表达“推测和可能性”，还是表达“虚拟”这一概念，只要是对过去已经发生的事情进行描述，一律用“情态动词+have done”这一结构；对现在或将来的事情进行描述，用“情态动词+动词或系动词原形”。
例如：（NMET2008山东，24）Thank you for all your hard work last week. I don’t think we ______ it without you.A. can manageB. could have managedC. could manageD. can have managed根据题干中所给出的时间last week可知我们已经做完了工作，已经完成，故排除A、C两项，再结合could have done表示虚拟语气以及与前面的I don’t think…，故说话者想表达的意思是：离开了你，我们本不可能完成这项工作。
故答案为B项。
★下面我们来看看常考的一些情态动词★以下试题均来源于往年的高考试题，具有很强的针对性(1) must表示推测，意为“一定……”，只能用于肯定句中。
must have done意为：一定做过某事或某事肯定发生了。
例如：—She looks very happy. She ______ have passed the exam.—I guess so. It’s not difficult after all.A. shouldB. couldC. mustD. might【解析】句意为：她看上去很高兴，一定是通过了考试。
【答案】C(2) should (not) / ought (not) to在中表示根据常规或常识推测，表示“某事应该或不应该发生”，语气比must或can’t / couldn’t稍弱。
例如：—How’s your tour around the North Lake? Is it beautiful?—It ________ be, but it is now heavily polluted.A. willB. wouldC. shouldD. must【解析】should此处表示推测，意为“应该”。