情态动词讲解

1、情态动词一、情态动词的含义1.The boy could speak three languages when he was 12.2.May I have your name? 3.Shall we begin now? 4.You must obey the school rules. can和could的用法关于 “can的句子1.表表“能力能力”Some dogs can smell out drugs(毒品毒品).一些狗能够嗅出毒品。2.表表“许可许可”Can I use your iphone?3.表示表示“推测推测”，用于否定句中表示，用于否定句中表示“不可能不可能”You ca

2、nt be tired. You have only been working for an hour.你不可能累，你仅仅工作了一个小时。 4.表示客观的可能性，意为表示客观的可能性，意为有时可能会有时可能会 Everyone can make mistakes in his life . 5.表示表示“惊讶惊讶”“”“怀疑怀疑”态度态度 How can you be so careless?could 1.表示can 的过去式 He can speak three languages. He could speak three languages when he was three year

3、s old. 2. 表示现在的“能力和许可”，语气比can 委婉 Could come to see you tomorrow? Yes, you can.(答语只能用can)/No ,Im afraid not.can 的习惯用法1.cant help doing sth 忍不住；不禁我情不自禁的笑了起来。I cant help laughing.2.cant (help) but do只好做某事 ;不得不I cant help but wait for her.3.cant .too. 再再. 也不为过也不为过You cant be too careful when driving.开车时

4、你再小心也不为过。have done 结构1.can /could have done 或cant /couldnt have done 表示对过去事情的推测表示对过去事情的推测 You couldnt have seen him last night.I saw him off at the airport. 2.could have done 表示对过去的虚拟，意为本能够做某事 You could have done better,but you didnt try your best.May 和might 的用法 1.表示征求意见或请求许可表示征求意见或请求许可 May use your

5、 car? Yes, you can.might 更加委婉 2.表表“可能可能” The road may/might be locked. a.might 表示过去的可能 b.might 表示现在的可能，比may 的可能性小 3.may 位于句首表示祝愿位于句首表示祝愿 May you be happy! May you succeed! 4.习惯用法习惯用法 May /might as well do sth (最好，不妨最好，不妨） 我最好还是去。 I might as well go. 5.have done 结构结构 a.may/might have done 表示对过去事情的推测表

6、示对过去事情的推测 Nobody answered the door. They might have fallen asleep. b.might have done sth 表虚拟，意为“本来可以” You might have given him more help.must的用法 1.表表“必须必须” Plants must have water in order to live. 植物必须有水才能活。 must 主观 have to 客观 2.表表“推测推测”，意为，意为“准是，一定准是，一定” a. must+v 对现在情况的推测对现在情况的推测 He must be dad.他准

7、是疯了。 b.must+be +ving 对将来或现在进行时的推测对将来或现在进行时的推测 It must be raining tomorrow.明天一定胡下雨。 c.must have done sth 对过去事情的推测 She didnt come to school.She must have been ill. 3.must 用于疑问句中，表示责备或抱怨，译为“偏要或非得” Must we hand in our homework today? Yes, you must. 4.mustnt 意为“禁止” Cars mustnt be parked here.will 的用法 1.w

8、ill 用于第二人称的疑问句表示征求意见用于第二人称的疑问句表示征求意见 2.will / would 表示个人意愿表示个人意愿,意为意为“要；愿要；愿” 3.will /would 表示表示“习惯性，经常性习惯性，经常性”，意为，意为“总是，老是总是，老是” 4.will/would 表示事物的功能或倾向性，意为表示事物的功能或倾向性，意为“能，行能，行” I will do my best to help you. When he was there,he would go to that coffee shop after work every day. The door wont op

9、en. Would you accept this invitation? 征求意见时would较will 委婉客气个人意愿个人意愿某种习惯，某种习惯，经常性经常性事物的功能事物的功能征求意见征求意见 5.would have done 表示对过去的虚拟，表示对过去的虚拟，意为本来可以意为本来可以 John didnt work hard at his lesson,otherwise he would have passsed the exam.shall的用法 1、用于第一、第三第一、第三人称的疑问句疑问句，表示征求意见 Shall we begin our class? Shall he

10、 come to see you? 2、用于第二第二、第三第三人称的陈述句陈述句，表示命令、威胁、警告或承诺She shall study,or she shall leave the college.He shall have the book when I finish reading.警告警告承诺承诺 3.shall 表示法律条文和规章制度中的要求意为（按照规定）必须，应该 Persons under 18 shant be employed in work.should 的用法 1、表示责任、义务、劝告、建议，意为、表示责任、义务、劝告、建议，意为应该应该 Studnts should

11、 respect teachers. They should be ready by 12:00. 2.在肯定句中表示推测，意为在肯定句中表示推测，意为“按理应该按理应该” It should be a fine day tomorrow. Its 4 oclock.They should be in New York now. (可能性比must小） 3.表示惊讶、赞叹或不满情绪，意为“竟然会” I cant imagine that such a well-dressed man should be so rude. 4.should /shouldnt have done sth ，对过去的虚拟 意为“本应该、本不应该 They should have finished their homework.need的用法 1.need在肯定句中多用于实义动词在肯定句中多用于实义动词 He needs to finish it this evening. 2.做情态动词多用于否定句、疑问句、条件做情态动词多用于否定句、疑问句、条件句句 I neednt use a clock to wake me up because at six oclock each morning