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课件网) Unit 2 Book 2 Let’s celebrate! Using language: Grammar Review In Unit 1, we’ve learned the following modals: be able to dare had better need have to That is why Letters from Father Christmas could be the perfect book. They might not receive their presents if they were not good. The children must have been very excited as they opened it. What do the words in bold indicate: an order a request, ability or possibility possibility Presentation. 情态动词表推测 must, can, could, may, might 情态动词表推测 情态动词+动词原形 情态动词+完成式 （表示对目前/将来的动作或状态进行推测） （表示对过去情况的推测） 情态动词must, can/could, may/might均可表示推测, 它们可以对过去、现在或将来的情况作出语气强弱不同的推测。 （对此时此刻正在进行的情况进行推测） 情态动词+be+动词ing形式 1. 对现在或将来的情况进行推测时，用“情态动词+ do”。 You must be Mr. Smith. I was told to expect you. Our team might win the race. 3. 对过去的情况进行推测时，用“情态动词+ have done”。 2. 对此时此刻正在进行的情况进行推测时，用 “情态动词+ be +动词-ing形式”。 She may be waiting for you in the entrance hall at the moment. The police are stopping all cars. They must be looking for the escaped prisoner. Presentation. 情态动词表推测 It must have rained last night, for the ground is wet. 情态动词+动词原形 情态动词 肯定式 否定式 疑问式 must 准是，一定 / / can 可能 can’t不可能 有可能吗 could 可能 couldn’t不可能 语气比can弱 may 或许，也许，说不定 may not 可能不 / might 或许，也许（比may弱） might not 可能不 / Look at his new car. He must have a lot of money. As a human being, anyone can make a mistake. He could be on his way home. He may be very busy now. They might have a lot of work to do now but I’m not sure. 1. 表示肯定的推测时： 各情态动词语气从弱到强依次为 might < may < could < can < must； --Can the news be true --It can’t be true. It may not be a great suggestion. 2.表示否定的推测时： can’t / couldn’t语气较强“不可能”； may not / might not语气较弱“可能不”。 1. He is right. 2. He must be right. 3. He can be right. 4. He could be right. 5. He may be right. 6. He might be right. must have done 过去一定。表示对已经发生的事情的肯定推测，语气较强。 eg It must have rained last night. The ground is wet. 情态动词+have done should/ought to have done 过去不可能做过。表示对过去发生的事情的否定推测。 eg They can’t have gone out, because the light is on. can’t / couldn’t have done Presentation. 情态动词表推测 may / might have done 可能已经。表示对已经发生过的情况的肯定推测，语气稍弱。 eg He may / might have given you more help, even though he was busy. 否定形式：may/might not have done 过去可能没有做过 could have done 本应该（却没有做）。含有责备或后悔之意。 eg They should have finished their work before playing. should/ought to have done 本可以。表示过去本来能够做某事而实际上没有做。 eg He could have passed the exam, but he was too careless. Presentation. 情态动词表推测 否定形式：should not have done本不该做却做了 ought not to ... ...
