语法突破 情态动词（课件PPT）-【学海风暴·PK中考】2023中考英语备考（安徽专用）

八年级下册 第10讲 Units 3-4 情态动词 初中英语 1 1 定义 本身有一定的词义， 表示说话人的情绪、 态度或语气的动词。 常用词 can (could), may (might), must, shall (should), will (would), had better, have to, need 等。 用法与特点 1. 有一定的词义，但并不完整，必须与实义动词一起构成谓语。 I can sing very well. She can dance beautifully. 2. 后接动词原形，即不带to的不定式。 She may lose her way in the village. You must do it now with his help. 3. 无人称和数的变化。 We must stay here at this time. He must stay here at this time. 4. 具有助动词作用，可以用来构成否定句，疑问句及用于简单回答。 （否定句） （疑问句） （简单回答） We can’t carry the heavy box. Can you sing an English song? →Yes, I can. / No, I can’t. 特殊用法 1. 以May开头的一般疑问句，否定回答常用mustn’t。 （否定回答） May I dance here after dinner? →No, you mustn’t. 2. 以 Must开头的一般疑问句，否定回答常用needn’t/don’t have to。 （否定回答） Must I read books every day? →No, you needn’t. /No, you don’t have to. 3. 情态动词表推测。 (1) 在肯定句中一般用must (一定), can/could(可能), may/might (也许, 或许)。 He may know the answer to this question. It is cold in the room. They must have turned off the heating. (2) 在否定句中用can’t / couldn’t(不可能)，may not/ might not(可能不)。 It can’t be the headmaster. He has gone to America. He will be back in two weeks. He may not know the scientist. I’m not sure. 易错警示 _______ she_______ her uniform to school today?  A. Need; wear         B. Does; need wear          C. Does; needs wear          D. Need; wears 【点拨】need作实义动词时，有两种用法：1. need to do sth.需要做某事 2. need doing sth. 需要被做某事（=need to be done sth.）；作情态动词时，后加动词原形，通常只用于疑问式或否定式。 【答案】A 易错警示 —Could I come later tomorrow? —Yes, you _______. 　 A. can B. could C. do D. can’t 【点拨】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，肯定回答应用can，否定回答可用No, I’m afraid not. 【答案】A 高频考点 —Is that Mr. Zhou? —It ______ be him. He has gone to Beijing. A. may B. can C. can’t D. mustn’t （海南中考改编） 解析：考查情态动词表推测的用法。由答语He has gone to Beijing “他去北京了”，可推断那个人不可能是周老师，表示否定推测。 答案： C —Must I finish reading the book today, Mr. Brown? —No, you __________. You can finish it in two da