1、助动词所谓助动词，是和本动词合在一起，用来表现时态，语态，语气的动词，除此之外，助动词也能用来表示疑问，否定，强调等意思 。一：助动词的特点1. 其后须接原形动词例句：He can speak English ( r )He can speaks English ( w )2 现在式中主语为第三人称单数，字尾不加 sHe cans speak English (w)3. 形成否定句时，在助动词后加 not例句：He can not speak English( r ) He doesns can speak English ( w )4. 形成疑问句时，将助动词放在主语前。Can he spe
2、ak English ?( r )Does he can speak English ( w )5 两个动词不能连用You will can swim soon ( w )二，助动词的用法1.can(could)can 是用来表示能力，许可，可能的助动词，而 could 是 can 的过去式A：表（能力） （=be able to）1. He can speak Japanese,but he cannot write it (他会说日语，但不会写)2. She tried to tie the rope , but she couldnt （她设法绑这条绳子，结果绑不起来）B：表 （可能）1
3、. It can not be true (那不可能是真的)2. A quarrel can sometimes cause trouble (口角有时候可能发生问题)C 表（许可）1. You can come in if you have a ticket( 如果你有门票就可以进来)2. I am afraid you can not park your car here (恐怕你不可以把车停在这里 )3. Can I leave early because I am not well doday?(因为我今天不舒服，我可以早点离开吗？)ertainly（可以）： 表（请求）1. Can
4、you do me a favor ?(你能帮我吗？注意：Could you do me a favor ?是更客气的说法。一般来说，针对自己的行为会用 Can I .?而针对对方的行为则用 Could you ?2. Could you repeat your cell phone number ,please ?(请你重复一遍你的手机号码好吗？)2.May (might )A: 表（许可）1. You may not chew gum in class(你不可以在课堂上嚼口香糖。 )2. May I interrupt you ?-Sure (我可以打扰你一下吗？-好的。)B 表 （可能）
5、1. You may bi right but I am against your opinion(你可能是对的，但是我还是反对你的意见)2. His health may or may not turn for the better （他的健康状况可能会好转，也可能会恶化）注意; might 可用于现在或过去式。其所表示的可能性较 may 低C 表(祈愿)1May I never seee a sight like that again !(愿我不再看到那样的景色)2.May you succeed (祝你成功)3.Must A 表（务必，命令）1.You must return this
6、book by next Tuesday .(下周二前你必须归还这本书)2. You must not talk with your mouth full （你不可以在嘴巴有东西时说话）注意 ; must （必须） must not （ 不可以）3. Must I really attend the meeting ?(我真的必须参加那个会议吗？)-Yes , you must (是的，你必须)No , you need not (不，你不需要)No，you do not have to (不，你不必)重点： must = have to（必须） 。但 must 只能用于现在式，其过去式用 h
7、ad to，未来式用will have to， 完成式用 have had to 代替。1.I had to go to see the doctor because I caught a cold (因为我感冒了，我必须去看医生)2. You will have to replace this light bulb （你将必须更换这个灯泡）3. We have had to stay here because it it raining (我们必须一直呆在这里，因为外面正下着大雨)注意; 口语中，常用 have got to 代替 have to1. You have got to be m
8、ore patient , Mary .(Mary 你必须更有耐心)B： 1.You must be kidding 。(你一定是在开玩笑)注意;表推测是的 must，其否定用 cannot 代替。1. Sheis very young ,She cannot by over twenty (她非常年轻，她不可能会超过二十岁)C 表（必须）1.All men must die (人一定会死)4.Will Will 除表示（未来）之外，还有下列用法A 表（现在的推测）1.Mom will be downstairs now.(妈妈现在应该在楼下吧。)2.That will be his hous
9、e (那应该是他家吧！)B; 表（表主语强烈的意志，固执）1. The window will not open (窗户怎么也打不开)2. He will insist on his right (他要坚持他的权力)C；表（习惯，倾向）1 Accidents will happen.(事故总是会发生)2A drowning man will catch at a straw .(溺水者攀草求援)D：表（请求，劝诱）1. Will you bring me a ladder ?(麻烦你那个楼梯给我好吗？)2. Will you have one more coffee ？（你要不要再来杯咖啡？）
10、5.Would Would 是 will 的过去式，但其有独特的用法。A 表（客气的请求）1.Would you mind if I sit next to you ?2.Would you call me back later ?(请你稍后再打给我好吗？ )B：表（过去的习惯）常伴随着 sometimes often 等频率副词。1. Before they hadtelevision , people would listen to the radio（在有电视剧前，人们习惯于听收音机）2. Susan would often chat with us at this coffee sho
11、p .(Susan 以前经常和我们在这家咖啡馆聊天)C 表（过去的意志）1 You would not eat carrots when you were a boy (你小时候不肯吃胡萝卜 )6 Should A 表（义务）1.You should exercise more and eat less(你应该多运动，少吃东西 )2 The government should spend more money on education (政府应该多花点钱在教育上 )B 表（推测）1.Our guests should be here within an hour （ 我们的客人应该在一小时内会
12、到吧）2. I sent you e-mail yesterday ,so you should know abouttheinvitation ,( 我昨天寄电子邮件给你，所以你应该知道邀请函的事吧。)C 表（强烈的好奇）1.Who should make such a foolish mistake ?(谁会犯如此愚蠢的错误呢？ )2. How should I know it ?( 我为什么应该知道那件事呢？ )Ought to (应该) 语气较 should 强，在口语中常用。1. My bicycle ought to be here because I left it just besidethe telegraph pole .(我的脚踏车应该在这里，因为我就把它停在电线杆旁。)2. You oughtnt (to ) do so .（你不应该这么做）3. Ought we (to ) tell him about it (我们应该告诉他那件事吗 ?)注意：美式口语中，to 常省略。4.
