情态动词-must-,have-to-,have-got-to.ppt

你 去睡一觉。 2. 你 邀请他。 3. 你 照你父母的话办。 4. 你 抽这么多的烟。 You’d better get some sleep. You’d better not invite him. You should do what your parents tell you. You oughtn’t to smoke so much. 最好 最好不 应该 不应该 必须 不许 不得不 不必要 You must get some sleep. You mustn’t invite him. You have to do what your parents tell you. You haven’t got to smoke so much. Modal verbs (Ⅱ) must have to have got to must not / mustn’t don’t have to haven’t got to / hasn’t got to Must sb…? Do / Does sb. have to …? Have / Has sb. to …? （必须、应当） （必须、不得不） 表示义务、命令或必要，后面接不带to的动词不定式。 　 Soldiers must obey orders. We must keep our word. 2. must 用在否定句结构中表示“不允许、禁止” He must not leave his room. You mustn’t smoke in the office. 3. must用在一般疑问句中，肯定回答用must，否定回答用needn’t 或don’t have to —— Must I hand it in before five? —— No, you _________________________. —— Yes, you ______________. you needn’t. / don’t have to you must have to 由have + to组成。因此具有have的各种时态。 He is an invalid and has to have a nurse. She knew what she had to do. I shall have to reconsider my position. He is always having to exercise judement. 2. 在口语中，have got to 也可以表示义务和需要， 与have to 基本同义。 He has got to go right now. He hasn’t got to go just yet. 含义不同： must 表示说话人的主观思想，强调个人意志和主观的决心。 have to侧重于客观上的必要，强调客观条件作用的结果。 You must do it now. I have to go now. 3. 否定含义不同 在否定句中, have to表示不需要，must则表示不允许。 You don’t have to go there. You mustn’t go there. 2. 适用时态不同 must 只能用于一般现在时和一般过去时，（在间接引语中） have to 可用于更多的场合。 She said she must do well in her English. Don’t be late again. You ____ be here on time. A. may B. can C. must D. needn’t You ___ do it even if you don’t want to. A. can’t B. mustn’t C. needn’t D. have to 3. —— Must I take a bus? —— No, you ___. You can walk from here. A. mustn’t B. don’t C. don ‘t have to