初中英语情态动词ppt课件

1、情态动词,情态动词:本身有一定的词义,表示说话人的情绪,态度或语气的动词,（但不能单独作谓语, 只能和其他动词原形构成谓语。）,must,1) 表示必须、必要。是说话人的主观看法 You must come in time. 在回答一般疑问句时，不能用mustnt而用neednt, dont have to（不必）.但它本身的否定是mustnt （表禁止不准） - Must we hand in our exercise books today? - Yes, you must. - No, you dont have to / you neednt.,must,2) 表示推测、可能性（只用于

2、肯定的陈述句） 1 Youre Toms good friend, so you must know what he likes best. 2 Your mother must be waiting for you now.,Might and may,表示请求和允许。might比 may语气更委婉，而不是过去式 否定回答时可用cant 或mustnt，表示“不可以，禁止”。 -Might/ May I smoke in this room? - No, you mustnt. - May/Might I take this book out of the room? - Yes, you

3、can. (No, you cant / mustnt. ) 根据情景而定 用May I.？征徇对方许可时比较正式和客气，而用Can I.？在口语中更常见。,2）用于祈使句（用于肯定句的句首），表示祝愿。,May you succeed!,3) 表示推测、可能性 （不用于疑问句）。,might不是过去式，它所表示的可能性比may小。 1He may /might be very busy now. 2Your mother may /might not know the truth.,can, could,1) 表示能力 Can you lift this heavy box? Yes,I c

4、an/No,I cant Mary can speak three languages. Can you skate? Yes,I can/No,I cant,2) 表示请求和允许。,-Can I go now? - Yes, you can. / No, you cant. 此时可与may互换。在疑问句中还可用could, might代替，不是过去式，只是语气更委婉，但不能用于肯定句和答语中。 - Could I come to see you tomorrow? - Yes, you can. ( No, Im afraid not. ),3) 表推测可能性。,肯定句中：can表示理论上的

5、可能性,推测； In Chongqing, sometimes it can be really cold. 否定句和疑问句中，只能用can表猜测可能性。 Someone is knocking at the door, and who can it be? It cant be Tom because he has gone to Beijing.,四、 shall,shall 用于第一人称，征求对方的意见。 What shall we do this evening? shall I clean the room for you?,2) shall 用于第二、三人称，表示说话人给对方的命令

6、、警告、允诺或威胁。 1. You shall fail if you dont work hard.(警告) 2. He shall have the book when I finish it.(允诺) 3. He shall be punished.(威胁),五. should,表示“应该”，常用来表示劝告、建议；认为“某人应该做某事”或“有义务责任做某事”。 We should obey traffic laws. You shouldnt watch TV every day。 You shouldnt have made this kind of silly mistakes. T

7、om should have brought his report today.,2) Should 也可表推测，但它是有一定根据的推测，意为“可能、该”,-When can I come for the photos? I need them tomorrow, -They _ be ready by 12:00,3）表示惊讶的语气,-You can never see such a man should be so rude to a lady.,六： will 和would,1)表示意志或意愿：决心，愿意， We will do our best to save the child. 我

8、们会尽力抢救这个孩子。 I told her to stop crying, but she just wouldnt listen. 我叫她别哭,可她就是不愿听。,2)表示请求、建议或征求对方意见时，用Would you.? 比用Will you.?更婉转。,Will/Would you please keep the door open?请让门开着好吗？ Will/Would you go with me?你愿意和我一起去吗?,七。need,1need作情态动词无人称或数的变化， 后接动词原形，多用于否定句和疑问句中。 如：You neednt worry.你不必担心 You neednt

9、 help me when I in trouble.,2由need引出的一般疑问句，肯定回答常用must或have to;否定答语常用neednt. 如：,Need I answer the question? 我需要回答那个问题吗？ Yes, you must. -Yes, you have to.是的，你必须回答。 -No, you neednt./you dont have to不，不必了。,由must引出的一般疑问句，肯定回答用must,否定答语用neednt/dont have to。,Must I do the work now? 我必须现在干这个活吗？ Yes, you must /have to. -No, you neednt /dont have to.,Need 做实义动词,Need to do sth需要做某事 它的否定和一般疑问句需借助于助动词do/does Eg:I need to do housework