职教高考英语专题复习（十二）—— 情态动词

职教高考专题复习（十二）—— 情态动词 知识链接 情态动词是指表示说话人的语气或者情态的动词。它表明说话者对某一行为的态度和观点，包括能力、判断、需要、可能、各种意愿等。 (一)情态动词本身有一定的词义，没有人称和数的变化，在句中不能单独作谓语，必须与其后的动词原形一起构成谓语。情态动词的否定形式：直接在其后加“not”。情态动词的一般疑问句：直接把情态动词提到句首，其他成分不变，并在句尾加问号。 有些情态动词有现在式和过去式两种形式，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。情态动词属不及物动词，故没有被动语态。 (二)常用的情态动词有： 1. can, could (1)表示能力,与 be able to 同义。can 只有现在式和过去式，be able to可有各种时态。 如: I can speak two languages. 我会说两种语言。 He could swim when he was five yearsold. 他五岁的时候就会游泳了。 Will you be able to come to ourmeetingtomorrow? 明天你能来参加我们的会议吗? (2)表示可能性(could 表示的可能性较小)。如: Anyone can make mistakes. 任何人都可能犯错误。 He could be in the reading room. 他可能在阅览室。 (3)表示请求、允许(这时可以与 may 通用,但是 may 较为正式, could 比 can 委婉)。如: Can/May I borrow your bike? 我可以借你的自行车吗? Could you pass me that newspaper, please?请把那份报纸递给我好吗? 【注意】此时回答用 can 和 can't 回答,而不能用could。 —Could I use your pen? —Yes, you can. —No, you can't. (4)表示推测、怀疑，用于否定句、疑问句和感叹句中。如： She can't be in the playground. Someone saw her go shopping just now. 她不可能在操场。刚才有人看见她去购物了。 Can this be true? 这是真的吗? How can you be so careless! 你怎么这么粗心大意！ 2. may, might (1)表示客观的可能性(might 的可能性一般比may要小些)，用于疑问句首时要换成can。如: Take an umbrella with you. It may rain. 带上伞，可能要下雨。 She may be in the classroom. 她可能在教室里。 Can the story be true? 这个故事能是真的吗? 否定句中表示可能性时，can't 语气很肯定;may not语气不肯定。如: It can't be him. He has gone abroad. 那不可能是他，他出国了。 It may not be him, but I'm not quitesure.那或许不是他，但我不十分肯定。 (2)表示请求(疑问句)、允许(肯定句)(这时可以和 can, could 通用,但是 may 更为正式),might 比 may语气更委婉，而不是过去式。否定回答时可用 can’t 或 mustn’t,表示“不可以,禁止”。 如: ——May/Might I take this book out of the room? ——Yes, you can/may.(No, you can't/mustn't.) 3. shall, should (1) shall用于第一人称、第三人称疑问句首，征求对方的允诺。如： Shall I open the door for you? 要我为你开门吗? Shall she go now? 她现在可以走了吗? (2) should 表示义务、劝告、推测,意为“应该”。 如: We should study hard. 我们应该努力学习。 We should not read in the sun. 我们不应该在阳光下看书。 4. will, would (1)表示请求(would 比 will 更委婉),主要用于第二人称疑问句中。如： Will you turn on the light, please? 请你把灯打开好吗? Would you post this letter for me? 你能帮我寄这封信吗? (2)表示意愿。如: She said she would take care of the child.她说她会照顾这个孩子。 I would like a cup of coffee please. 我想要一杯咖啡。 (3)表示提供帮助或邀请。如： What will you have for breakfast? 你早餐吃什么? Would you like me to help you? 要我帮忙吗? 5. must, have to (1) must 和 have to 都表示“必须、一定”的意思。must表示主观上的必须和说话者的个人意志与权威性，have to 表示客观上的必要, 有“不得不”、 “只得”的意思。must的否定形式mustn't 表示“禁止”，一般不用于回答; 其否定回答要用 don’t have to 或 needn’t,表示“不必”。 如: I must lose some weight.我必须减肥。 You have to sign the check on the back.你必须在支票背面签名。 You mustn't play my camera. 你不许玩我的相机。 —Must I finish reading the book today? —Yes, you must. ——No, you needn't./No, you don't have to. (2)must 只能用在现在时和将来时的句子中, have to可用于各种时态。have to 的疑问句和否定句用 do, does 或 did 等作助动词。如: We must do our homework now. 我们现在必须做作业。 She has to go now because her motheriswaiting for her.她现在得走了,因为她妈妈在等她。 (3) must表示肯定的推测, 意为“必定,一定” 。 如: The light is still on, so he must be athome.灯还亮着，因此他一定在家。 6. need (1)need作情态动词时，常用于疑问句和否定句中，无人称和数的变化。如： ——Need I come? ——Yes, you must.(No, you needn't.) You needn't put on your sweater. 你不必穿运动衫。 (2)need用于实义动词时，后面常跟动词不定式、v.-ing、名词等，有人称、数和时态变化。如： You need to clean your room. 你需要把你的房间打扫干净。 She needs a good rest.她需要好好休息。 The bicycle needs repairing. 这辆自行车需要修理。 常考知识点： 1. may表请求许可时的肯定回答可以用can，而否定回答要用can't 或 mustn't。如: ——May I go now? —Yes, you can.或—Certainly.或—Yes, please. —No, you can't.或——No, you mustn't. 2. need的肯定回答用 must,否定回答用needn't。如: —Need I buy a computer? —Yes, you must. —No, you needn't. 3.must用于征求对方意见时，肯定回答用must,而否定回答要用 needn’t 或 don’t have to。如: —Must I return the book tomorrow? —Yes, you must. —No, you needn't. 或—No, you don't have to. 4.表推测时，表示不确定用may，通常用在陈述 句 当中，否定和疑 问 句中通 常 用Can...? 和 can't 意为可能吗和不可能。表肯定、一定用must。如: You must be hungry after all that walk-ing.走了那么远的路，你一定饿了。 That can't be Mary—she's in New York.那不可能是玛丽——她在纽约呢。 【专项训练】 1.—Must I water the flowers now, mum? —No, you_____ . You do it later. A. mustn't;must B. mustn't;may C. needn't;may D. needn't;must 2.—Who's singing in the garden? —It _____be Mr. Brown. He always practices singing at this time. A. must B. can't C. need D. could 3. I _____follow you. Would you please repeat it slowly? A. can't B. mustn't C. wouldn't D. shouldn't 4.—Excuse me, may I keep the book a little longer? ——Sorry. You_____ return it today. A. must B. mustn't C. can D. can't 5. Children _____sit in the front seat of a car. It's too dangerous. A. should B. needn't C. must D. mustn't 6.—I forgot to bring my dictionary. CouldIuse yours? —Yes, you_____ . A. can B. must C. could D. should 7.—The room is so dirty. _____we clean it? —Of course. A. Will B. Shall C. Would D. Do 8.—I don't mind lending you my dictionary.—You _____. I have already bought one. A. needn't B. mustn't C. can't D. shouldn't 9.—Don't get near to the lake. It is too dangerous! ---_________ A. Yes,I won't B. No,I don't C. No,I can't D. No,I won't 10. We _____pay for the ticket. It's free. A. can't B. mustn't C. might not D. don't have to 11. David,_____you please sweep the floor and take out the trash? A. could B. may C. might D. must 12. Here is my phone number. You _____call me anytime you like. A. must B. can C. should D. need 1 学科网（北京）股份有限公司 $$