Unit 2 Using Language (Modals 2) 课件-2022-2023学年高一英语外研版（2019）必修第二册

B2U2 Using language Modals (2) Modals What do the words in bold indicate: an order, a request, ability or possibility? The words in bold indicate possibility. must, should, can, could, may, might 都可表推测 两种句式： 情态动词+动词原形 情态动词+完成式have done （表示对目前的动作或状态进行推测） （表示对已发生情况的推测） Modals 情态动词表推测 must 表推测 1. must表示推测时意为“一定，肯定”，推测的语气最强。 He must be American. (= It is certain that he is American.) 他一定是个美国人。 2. must表示推测时，只能用于肯定句，不用于否定句和疑问句。 如果表示“一定不，肯定不”，应用can’t，不能用mustn’t，mustn’t表示“禁止”。如询问某种可能性时，应用can。 He must know my address. He can’t know my address. Can he know my address? 他肯定知道我的地址。（一定） 他不可能知道我的地址。（一定不） 他可能知道我的地址吗？（询问可能性） must 表推测 3. must表示推测时，可以推测现在的情况、正在发生的情况和过去已经发生的情况。 John must be at home. The light is on. It’s 12 o’clock. They must be having lunch. It must have rained last night, for the ground is wet. （现在） （此刻） （过去） must 表推测 Exercise 1. You ______ be hungry after all that long walking. 2. - It might be John who is in the office. - No, it ______ be him. I saw him off at the airport half an hour ago. 3. He ___________________ (complete) his work; otherwise, he wouldn’t be enjoying himself by the seaside. must can’t must have completed can/could 表推测 can用于肯定句时，表示有时可能会出现的情况。 can表示对现在的动作或状态进行主观的猜测时通常只用于否定句和疑问句。 1. Jogging can be harmful to the health. 2. You can’t be hungry, for you had lunch only two hours ago. 3. Can he be our teacher? can/could 表推测 can’t/couldn’t have done 表示对过去事实推测，意为 “不可能做过……”。 4. He couldn’t have watched TV yesterday for he knew he would have an exam. 昨天他不可能看电视了，因为他知道快要考试了。 can/could 表推测 Exercise Although you ______ find bargains in London occasionally, it’s generally not a cheap place to shop. 2. Thank you so much Sir! Without your help I ________________ (pass) the test. 3. Mr. Smith is on time for everything. How __________ it be that he was late for the important meeting? can couldn’t have passed can/could may/might 表推测 1. may/might表示把握不大的推测，用于肯定句和否定句，不能用于疑问句。might在语气上比may更委婉，表示的可能性更小。 He may/might be America