人教版高中英语必修三unit1grammar.pptx

Unit 1 Festivals around the worldGrammar情态动词（Modal Verbs)情态动词表示说话人对某一动作或状态的态度，认为“可能”、“应当”、“必要”等等。但本身词义不完全，不能单独作谓语动词，必须和不带to的不定式（即动词原形）连用。情态动词没有人称和书的变化。can and couldmay and mightwill and wouldshall and shouldmust and can’t can and couldSo he can carry heavy books.ability He couldnt open the door by himself. abilityCould you open the door, please? requestcan and could1)??表示能力（ability），指有能力做某事，意为“能够”。例如：注意：表示现在，将来“能够”可用be able to 替换。表示过去“能够”并成功了只能用was/ were able to, 不能用could。例如My grandma is over eighty, but she can/ is able to read without glasses.We can/ will be able to talk about the matter later. I talked with her for a long time, and at last I was able to make her believe me.(不能用could) can and could2)?表示请求（request）或（permission)意为“可否”、“可以”。 Could 比can 更有礼貌，在此不是can的过去式。 Can you wait a moment please?Liz, can you do me a favor?Excuse me, could you tell me the way to the station?I wonder if you could help me. (request) ---- Could I use your phone? ----Yes, of course. You can. Do you think I could borrow your bike? (permission) can and could3) 表示可能性 （possibility） a. can 表示泛指的“可能”，并非说话者主观认为的可能性，即并非说话者的主观猜测。Accident can happen to any drunken driver. b.表示说话者主观猜测，只能用与否定句或疑问句中。例如：It can’t be my father. He is now in England. ----Can it rain tomorrow?----No, it can’t. may and mightHe may be in his office.=( perhaps he is in his office.)He might be having lunch.=( perhaps he is having lunch.)may and might1） 表示可能性（possibility）,用于对现在，过去或将来的推测，暗示不确定。might 不是may的过去式，它所表示的可能性比may 小，含较多的怀疑。He may be very busy now. (可能性较大)He might be very busy now. (可能性较小) may and might2） 表示许可（permission），表示允许别人做某事， 也可征求对方的许可。He may go now.We may keep the book for two weeks.3） 用于祈使句，表示祝愿。May you succeed!May you have a nice trip! may, might, can, could表示猜测might1. They (can/might) ___________be away for the weekend but I’m not sure.2. You (may/might) __________leave now if you wish.3. (could/may) __________you open the window a bit, please?4. He (can/could) __________be from America, judging by his acce