必修三英语unit1情态动词的用法

1、Modal Modal VerbVerb情态动词情态动词情态动词表示说话人的情态动词表示说话人的语气语气和和情情态态的动词。的动词。语气语气：能力、义务、建议、允诺、：能力、义务、建议、允诺、许可、推测。许可、推测。情态情态：情感和态度。：情感和态度。观察下列各句，注意谓语动词形式。1.He can finish the paper in an hour.2.Would you please pass me the dictionary?3.She may be very busy now.4.I will never forget the days we spent together.5.W

2、e should help each other.情态动词的语法特征情态动词的语法特征1.1.不能单独做谓语，即是情态动词不能单独做谓语，即是情态动词+ +动词原形。动词原形。 例如：例如：I I can swimcan swim. .（谓语）（谓语） ( (除除ought to ought to “应该应该”和和have tohave to“不得不不得不”外外) ) 2.2.情态动词没有人称，数的变化。情态动词没有人称，数的变化。3.3.有些情态动词有一般式和过去式，过去式比一有些情态动词有一般式和过去式，过去式比一般式更委婉。般式更委婉。 如如can-could , will-would,

3、 may-might,can-could , will-would, may-might, shall-should shall-should建议建议, 请求请求, 允许允许, 能力能力Jim isnt good at maths, but he can speak English well.May I have a look at your Iphone?Would you like to join my family for dinner?When going by plane, you should arrive on time.When you eat fish, you must b

4、e very careful with the bones. 能力能力请求请求/允许允许请求请求建议建议建议建议情态动词语法目录 一、一、can / could 二、二、may /might 三、三、will /would 四、四、shall / should 五、五、must I can/ am able to swim.I could/ was able to climb a tree when I was a child.I will be able to swim next week.The fire spread through the hotel very quickly but

5、everyone was able to get out 1. can 表示现在的能力表示现在的能力2. could表示过去的能力表示过去的能力3. be able to 表能力，可用于多种时态表能力，可用于多种时态4. be able to 强强调某人通过努力克服调某人通过努力克服困难成困难成功地做了某事功地做了某事一、情态动词表能力一、情态动词表能力2. 表表“许可许可”，译为，译为“可以可以”，could比比can语气较委婉。用语气较委婉。用can 或或cannot / cant 回答回答 -Can /Could I borrow your bike for a moment?-Yes,

6、 you can. / No, you cant.3. 表表“可能性可能性”，译为，译为“可能可能”；Can this news be true?Where can they be?否定句中，翻译为否定句中，翻译为“不可能不可能”She cant have left school, for her bike is still here. 情态动词情态动词 含义含义否定式否定式 注意点注意点can / could表能力表能力“能，会能，会”cant“不会，不能不会，不能”区别区别 be able to表许可表许可“可以可以”cant “不可以，不许不可以，不许”代替代替may表推测表推测“可能可

7、能”cant “不可能不可能”主要用于主要用于否定、否定、疑问句疑问句中中1表示某人通过努力克服困难做成某事表示某人通过努力克服困难做成某事,要用要用was / were able to.2 could, might, would 表委婉语气用于疑问句表委婉语气用于疑问句, 答语仍须用答语仍须用 can, may, will.3 can 用于肯定句中用于肯定句中, 可表示可表示”有时可能有时可能”情态动词情态动词 含义含义否定式否定式 注意点注意点can / could表能力表能力“能，会能，会”cant/couldnt“不会，不能不会，不能”区别区别 be able to表许可表许可“可以可

8、以”cant /couldnt“不可以，不许不可以，不许”表推测表推测“可能可能”cant /couldnt“不可能不可能”主要用于主要用于否定、疑否定、疑问句问句中中补充：金版补充：金版12页右边第页右边第4点点May I eat KFC if I finish my homework?may/might:1. 表示许可。表示请求、允许时，表示许可。表示请求、允许时，might比比may的语气更委婉一些。的语气更委婉一些。 Might/May I use your computer? Yes, you can. /No, you cant/you may not / you mustnt.

9、may/might:2.用于祈使句中表示祝愿。用于祈使句中表示祝愿。3.表示推测、可能（只用于肯定句，表示推测、可能（只用于肯定句，疑问句则要用疑问句则要用can或或could）。）。 祝你成功！祝你成功！ May you succeed. He may be very busy now. May you be happy all your life. 情态动词情态动词 含义含义否定式否定式may /might表许可表许可“可以可以”mustnt 不许，严禁不许，严禁may not 最好不要最好不要表推测表推测“可能可能”may not 可能不可能不 will 和和 wouldWill you

10、 give him a message when you see him. 用于第二人称，表用于第二人称，表“询问意愿，提出询问意愿，提出请求请求”would you(用于现在时用于现在时)语气更为婉转语气更为婉转2. We will help him if he asks us to. 表表“意志，意愿意志，意愿”，译为，译为“会会”过去时：过去时：would I promised that I would do my best. 3. He will always take a walk after supper. 习惯上会发生的事情习惯上会发生的事情During the vacation

11、 he would often visit me.(过去式过去式)4. 某种特定情况下真实或可能的事情某种特定情况下真实或可能的事情 At that time, people would starve if food was difficult to find.情态动词情态动词 用用 法法will1.表请求表请求(第二人称第二人称)2.表意志表意志,意愿意愿3.表某种表某种倾向或倾向或习惯习惯4.某种特定某种特定情况下真实情况下真实或可能的事或可能的事情情would更客气的更客气的请求请求过去的意志过去的意志,意愿意愿过去的过去的倾向或倾向或习惯习惯过去某特定过去某特定情况会发生情况会发生的事

12、情的事情shall:1.Shall用于第一、第三人称疑问用于第一、第三人称疑问句中，表示说话人征求对方的意句中，表示说话人征求对方的意见、向对方请示或提供帮助见、向对方请示或提供帮助 。1.Shall we begin our lesson? 2.When shall he be allowed to leave hospital? 3.Shall I carry this bag for you?shall:2.Shall用于第二、第三人称，表用于第二、第三人称，表示说话人给对方命令、警告、允示说话人给对方命令、警告、允诺或威胁。诺或威胁。 You shall fail if you don

13、t work harder. He shall be punished according to the rule. He shall have the book when I finish it. 警告警告威胁威胁允诺允诺 should 1. Young people should respect old people. should 表表“义务，建议义务，建议”。 2. Its five oclock. John should be at home now. 表推测，按道理应当。译为表推测，按道理应当。译为“理应，估计理应，估计We have prepared a fridge of go

14、od and drinks. That should be enough for the party.3.表示表示 “竟然竟然” Its a pity that he should be so rude to a lady. 情态动词情态动词 用用 法法 shall征求对方意见征求对方意见(第一第一, 三人称三人称)表示命令表示命令,警告警告, 威胁威胁或允诺或允诺 should / ought to表示劝告表示劝告,建议建议,命令或责任命令或责任“应该应该, 必须必须”表示推测表示推测, “理应理应, 估估计计, 大概大概”should 还还可表示可表示“竟然竟然”must 表“必须” do

15、nt have to dont need to neednt Must we hand in our exercisebooks today? Yes,you must/ No,you dont have to 2.1. 不必须不必须mustnt 禁止 表表“推测推测”时：时： 肯肯: must be +表语表语 (一定一定） 否否: cant (不可能不可能) e.g. That cant be Mary. She is in New York.3. have to “不得不不得不”，表客观需要，表客观需要情态动词情态动词 含义含义否定式否定式注意点注意点must表必要表必要“必须必须”ne

16、ednt“不必不必”( 区别区别 have to)有时表有时表“偏要偏要”表推测表推测“一定一定” cant“不可能不可能”只能只能用于用于肯定肯定句，句，不能不能用于用于否定、疑问句否定、疑问句You _ buy a gift, but you can if you want to.must B. mustnt C. have to D. dont have to2. When I was young, I was told that I _ play with fire. A. wouldnt B. neednt C. mustnt D. darent3. - May I smoke he

17、re ? - If you _, choose a seat in the smoking area. A. should B. could C. may D. must情态动词表推测情态动词表推测可能性的强弱层次must should/ought to can/could may/might1. That _ be Anns husband, for I am sure that he doesnt wear glasses.A. cant B. may not C. mustnt D. neednt 2. - Good morning. I got an appointment with

18、Miss Smith yesterday. - Ah, you _ be Mr. Peter.A. might B. must C. would D. can3. What do you mean, there are only ten tickets? There _ be twelve.A. should B. would C. will D. shall4. It is usually warm in my hometown in March, but it _ be rather cold sometimes. A. must B. can C. should D. would5. A

19、lthough this _ sound like a simple task, great care is needed. A. must B. may C. shall D. should32阅读下列学生书面表达常见错误句子并改正：1.Thanks to your help,I can back to school again.2.You will happy when you get a gift.3.You can be taken Bus No.3 to the theatre.4.We should to help each other.5.You can coming a lit

20、tle earlier.6.You must be return the book before the Summer vacation.7.I will waiting for you at the entrance .8.You should bought a small gift when you visit a friend of yours.go backbetakecomewaitbuy33假如你是李华，你的美国朋友Jack四月份即将来中国旅游，写信向你了解你所在城市的天气、食及交通等方面的情况。请你根据提示用用英文给Jack 写一封回信。1.四月天气暖和，四月底有点热，建议他带薄

21、外套、T恤和短裤。2.饮食：有很多中国传统小吃（介绍一两样），如果不习惯中餐，可以去KFC。3.交通：从机场到你所在城市开车大概2个小时。建议他做大巴比较便宜，打出租车很贵。4.希望Jack 能多呆几天，以便你可以带他游览风景名胜。注意：1.可根据情况增加细节以使行文流畅 2.字数100左右。 3.参考词汇： T恤和短裤T-shirt and pants 风景名胜places of interestDear Jack, I am very excited to know that you will come to China for sight-seeing in April.You want

22、 to know something about my city,now I am wtiting to tell you in detail._学以致用：根据提示写一篇小短文，注意谓语动词形式。34参考范文：Dear Jack, I am very excited to know that you will come to China for sight-seeing in April.You want to know something about my city,now I am wtiting to tell you in detail. It is warm in my city in April,but it can be a little bit hot at the end of this month.Thus you dont