1、考点四情态动词一、情态动词的基本用法情态动词用法例句can/could表示能力，意为能，会。表示客观可能性，意为有时会；可能。表示推测，通常用于否定句和疑问句中，can比could语气强。Dont worry yourself about me， I can take care of myself.你别担心我，我能照顾好自己。She cant be Mary， because Mary is in hospital. 她不可能是玛丽，因为玛丽住院了。may/might表示请求和许可，意为可以。在疑问句中，might比may的语气更委婉。表示推测，意为可能。通常用于肯定句和否定句中，might比
2、may的可能性要小一些。Might I go fishing with you tomorrow？明天我可以和你一起去钓鱼吗？Yes， you may/can. 是的，你可以。shall表示命令、警告、允诺或威胁等。用于主语是第二人称或第三人称的陈述句中。Tell Jerry he shall get a gift if he behaves well. 告诉杰里，他如果表现得好，会得到一个礼物。should表示责任、义务、劝告、建议等，意为应该。表示推测，意为按理应当，估计。表示意外、惊讶、忧虑、惋惜等情绪，意为竟然。You should learn to respect the elder
3、s. 你应该学会尊重长辈。Its strange （that） you should say that. 你这么说真奇怪。must表示义务、必要性等，意为必须。在回答由must引起的一般疑问句时，若为否定回答，通常用neednt或dont have to。表示很有把握的肯定推测，通常用于肯定句中，意为准是，肯定是。mustnt表示不许，禁止，是强制的命令。Must I hand in my paper now？我现在必须交论文吗？Yes， you must./No， you neednt （dont have to）. 是的，你必须。/不，你不必。will表示意愿、意志。表示请求。表示习惯，意
4、为常常做某事。would/used to表示过去的习惯。When my parents were away， my grandmother would take care of me. 我父母外出的时候，总是祖母照看我。need表示必要性，常用于疑问句和否定句中， neednt 表示不必。对need引出的一般疑问句作肯定回答时用must，作否定回答时用neednt。My room is very clean， and I neednt clean it today. 我的房间很干净，我今天不需要打扫它了。dare意为敢，胆敢，主要用于疑问句、否定句和条件句中。I darent say what
5、 I think. 我不敢说出自己的想法。have to表示客观需要，意为必须，不得不。You have to be back before 10 oclock because the train leaves at 10：05.你必须在10：00前回来，因为火车10：05发车。二、情态动词have done对过去的推测must have done过去一定做过can/could （not） have done过去（不）可能做过may/might have done过去可能做过对过去情况的后悔、遗憾或责备could have done本能够做（却未做）should have done本该做（却未
6、做）might have done本可以做（却未做）neednt have done本不必做（却做了）What a pity！ Considering his ability and experience， he could have done（do） better.Its 9：00 now. Jenny should have finished（finish） her homework.用适当的情态动词填空（必要时加not）1.I dont really like James. Why did you invite him？Dont worry. He may/might not come.
7、 He said he wasnt certain about his plans.2.I cant thank you too much for all your help to my son while we were away from home.3.I dont think you should give up because you have been practising for so long！4.When he worked there， he would have a walk along the river every morning.5.You know he wont
8、let us leave early if we dont get the work done.6.In my opinion， you should leave him alone for the time being to allow him to calm down.7.You mustnt play with the knife， or you may hurt yourself.8.Must I finish the job this Friday？No， you neednt. You may finish it before 6：00 pm.9.It must have rained last night， for the road is quite muddy.10.Whoever breaks the school rules will/should/shall surely be punished.
