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课件网) Unit 4 Grammar and usage Modal verbs How do you explain modal verbs 情态动词 情感 态度 情态动词，即表示人的情感和态度的动词。 情态动词 What Modal Verbs do you know 1.常见的情态动词 can, could, may, might, must, ought to, shall, should, will 和 would 共10个。 2.具有情态动词特征的词还有 dare, need, have to 和 used to （共4个）兼具情态动词和实义动词 （可直接做谓语）两种身份。 情态动词的常见特点： 1.情态动词有词义，表示“能力、可能性、必要性、建议等。 2.情态动词不能单独使用，它必须和另一个动词原形一起构成谓语. 3.情态动词无人称和数的变化，但是有时态的变化。 1. 能力———能够做某事（具备某种能力）； could主要指过去能够； Two eyes can see more than one. Could the girl read before she went to school 2. 建议 suggestion you can get ideas from different sources… You could also read book reviews in newspapers, in magazines or 3. 表possibility推测———意为“可能”，一般用于疑问句和否定句。 As we all know，anyone can make mistakes. That can’t be Kelly—she’s in New York. (“不可能是”) 1. can & could 4. could表示更委婉语气，征求许可，回答时只能用can；用于否定句中表不允许。 Could I have a look at your new pen 2. may/ might 1. 表请求许可，以may/might开头的问句中，否定回答中要用may not/can’t。 1)You may take this seat iy you like. 2)--May (Might) I ask for a photo of your baby --No, you may not/ can’t. 2. 表可能。might可能性小。 She may/might not know about it. 3.may还可用于祈使句表示祝愿。 May you succeed! have to “必须、不得不“，强调 客观需求，有时态的变化（has to/ had to / will have to...) 否定形式为 don‘t / doesn’t / didn‘t have to... （没必要） 相当于 needn’t We will have to think of a new plan. You don't have to run. 3. have to 4. must 1. 用于肯定句中表说话人必须做某事； 否定 mustn’t 表禁止。 1)You must keep your word. 2) Cars mustn’t park in front of the entrance. 2. 表示肯定的推断。意为“想必、准是、一定”等， 只用于肯定句。 1) He must be ill. His cheeks are so pale. 2) There must be other ways to solve the problem. 否定句用can’t 表 不可能。 3. 在以must 开头的疑问句中，肯定回答用must; 否定回答用needn’t 或don’t have to。 —Must he hand in his exercise books now —Yes, he must. / No, he needn’t. / No, he don’t have to. （1）shall:表征询意见或建议,多与I或we连用。 1) What shall we do this weekend 2) When shall my brother be able to leave hospital (2) 常用于主语是第三人称的条约、法律法规、规章制度等文件中表“义务”或“规定”。 Every student shall wear school uniform at school. 5. Shall/should/ought to ①表示建议、劝告≈ ought to；②也可表示推测 You should go to class right away. The film YOLO should be great as it was directed by Jia ling. You should be polite to your teachers. They should be home by now. 建议/职责 推测 建议/职责 推测 should We ought to make a careful plan before we start the work. ① They ought to apologize. ② You are his brother so you ought to take care of him. 1. ought to: 应当；应该 ，意思接近于should，但ought to语气更强。 2. 表示建议或劝告。 3. 表示推测 ... ...
