,Festivals around the world,情态动词用法,Period 3&4,1、Lead-in,看图讨论：,教师在黑板上写下三个答案，请学生讨论： 1.So he can carry heavy books. 2. He couldnt open the door by himself. 3. Could you open the door, please?),2、Explanation of the use of modal verbs,can 和could：,1) can的主要用法是： （1）表示能力（ability）,指有能力做某事，意为“能够”。 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:,1.My grandma is over eighty, but she can/ is able to read without glasses. 2.We can/ will be able to talk about the matter later. 3.I talked with her for a long time, and at last I was able to make her believe me.(不能用could),2)表示可能性（possibility）,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。如： Accident can happen to any drunken driver,3）还可表示说话者主观猜测，只能用与否定句或疑问句中。,如： It cant be my father. He is now in England.,2) could的主要用法是： 表示请求（request）或允许（permission）。意为“可否”“可以”。 Could 比can 更有礼貌，作该意理解时不是can的过去式。,如：Could you lend me your dictionary? Could I use your bike?,may and might,may 常用来表示： A. _ eg. May I come in ? You may go now. B. _,表请求，允许，比can更正式,表示猜测,eg. The guest may arrive this afternoon。 He may be very busy now.,C. _ eg. May you succeed! May you have a good journey!,表示祝愿;语气较正式:,might 的用法: 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。,eg. He might be very busy now. (可能性较小),will和would：,1）表示意愿 表示愿意做或主动提出做，如意志，愿望或决心等，,如：That bag looks heavy, Ill help you with it.,Thanks for lending me the money, Ill pay you back on Friday.,2）表示习惯,如：This old man is strange. He will sit for hours without saying anything. We would sit around Grandpa after supper, listening to his stories.,3）表示请求，用于第二人称,注：would比will更委婉，如：,will you come this way, please? Would you open the window?,shall and should,shall的用法:,a.shall 在疑问句中用于第一，第三人称，表示征求对方的意见。,b.shall 用于第二，第三人称，表示说话人给对方的命令，警告，允诺或威胁。,如： Shall Tom go there with me tomorrow? You shall fail if you dont work harder. He shall have the book when I finish reading it. He shall be punished.,（征求）,（警告）,（允诺）,（威胁）,shall and should,should的用法:,a. should 表示劝告、建议、命令。,b. should 表示期待，用于表达合理推断（prediction，意为“应该” ），或明显的结果（意为“可能”）且所期待的事几乎是事实。,如：1、你们应该马上去上课。 2.已经三点钟了，足球比赛应该开始了。,You should go to class right away.,It is three oclock, the football game should begin now.,must and cant,must 用来表示“命令”、“推测”等含义。,1）表示规定、指令 表示规定、指令时主要指客观上的法律、条文规定，常常翻译为“应该、必须”之类意思。注注：mustnt 表示禁止。如：,You must have a passport if you want to go abroad. Drivers mustnt drive after drinking.,2) 表示主观的命令、禁止 表示主观的命令、禁止时，主要指说话者主观的命令或强烈的劝告。,1.You can go out with your friend but you must come back before 11 at night. 2.-Must I hand in the exercise today? -No, you neednt.,3）表示猜测， 语气非常肯定，近乎确定的意味，一般用于肯定句，意为肯定。其否定为cant， 意为不可能,You must be ill. I can see it from your face. He cant be at home. I saw him in the classroom just now.,你肯定是病了，我能从你脸上看出来。,他不可能在家，我刚看到他在教室。,1. you wait a moment please? 2.Liz, you do me a favor? 3.Excuse me, you tell me the way to the station? 4. - I use your phone? -Yes, of course. You . 5.Do you think I borrow your bike.,3.课堂练习：一、填空,Can,can,could,Could,can,could,二，选择,1.-_ I go out to play, mum? -No, you_. You should do your homework first. A. Might; wouldnt B. May; had better not C. Must; mustnt D. Need; mustnt,B,2. -Where is Emma? -I cant say for sure where she is, but she _ be out shopping. can B. should C. Must D. may 3. The room is in a terrible mess; it _ cleaned. A. cant have been B. couldnt be C. may have been D. would be,D,A,4. How_ you say that you really understand the whole story if you have covered only part of the article? A. can B. must C. need D. may 5. There _ be any difficulty about passing the road test since you have practised a lot in the driving school. A. mustnt B. shant C. shouldnt D. neednt,A,C,Homework,Finish exercises on workbook P42-43.,Thank you !,