情态动词用法小结 (2).ppt
情态动词用法小结,榆中县第九中学李锦江,提出委婉的请求在回答中不可用could。-Could I have the television on?-Yes,you can./No,you cant.2.在否定、疑问句中表示推测或怀疑。He couldnt be a bad man.他不大可能是坏人。,用情态动词can,cant,may,must,mustnt,neednt,could 填空。,Could,cant,must,can,Must,neednt,can,情态动词的语法特征:1)情态动词不能表示正在发生或已经发生的事情,只表示期待或估计某事的发生。2)情态动词除ought 和have 外,后面只能接不带to 的不定式。(ought to+动词原形、have to+动词原形）,3)情态动词没有人称,数的变化,即情态动词第三人称单数不加-s。4)情态动词没有非谓语形式,即没有不定式、分词等形式。,have to和must1)两词都是“必须”的意思,have to 表示客观的需要,must 表示说话人主观上的看法,既主观上的必要。,My brother was very ill,so I had to call the doctor in the middle of the night.我弟弟病得很厉害,我只得半夜里把医生请来。(客观上需要做这件事)He said that they must work hard.他说他们必须努力工作。(主观上要做这件事)2)have to有人称、数、时态的变化,而must只有一种形式。但must 可用于间接引语中表示过去的必要或义务。He had to look after his sister yesterday.,3)在否定结构中:dont have to 表示“不必”,mustnt 表示“禁止”。You dont have to tell him about it.你不一定要把此事告诉他。You mustnt tell him about it.你一定不要把这件事告诉他。,could与can的区别：could与can都是情态动词,could是can的过去式。二者都可用于表示请求,但是用法稍有不同。can表示一般性的请求,语气随便，常用于熟人之间或长辈对晚辈,上级对下级的场合。,e.g.Can you tell us your story,Tony?Tony,你能给我们讲讲你的故事吗？could表示有礼貌的请求,语气委婉,常用于非熟人之间或晚辈对长辈,下级 对上级的场合。,e.g.Could you tell us if it snows in winter in Australia?Sure.请告诉我们,澳大利亚冬天下雪吗?当然可以。1.-_ you come and play with us now?-Im afraid I _.I _ do the cooking.I _ come later.2.-_ we clean the windows today?-No,you _.You _ clean them tomorrow.,3.-_ I watch TV this evening,mum?-No,you _.Work _ come first.4.-_ I come in,please?-Yes,please.5.Excuse me._ you tell me the way to the cinema?,May,mustnt,must,May,Could,典型例题1）-Could I borrow your dictionary?-Yes,of course,you_.A.might B.will C.can D.should,C,could表示委婉的语气,并不为时态。答语中of course,表示肯定的语气,允许某人做某事时,用can和may来表达,不能用could或might。复习:will 与you连用,用来提出要求或下命令。should与you 连用,用来提出劝告。,2）-Shall I tell John about it?-No,you _.Ive told him already.A.neednt B.wouldnt C.mustnt D.shouldnt,答案A.neednt 不必,不用。wouldnt 将不,不会的。mustnt 禁止、不能。shouldnt不应该。本题为不需要,不必的意思,应用neednt。,3）-Dont forget to come to my birthday party tomorrow.-_.A.I dont B.I wont C.I cant D.I havent,答案B.will既可当作情态动词,表请求、建议、也可作为实义动词表“意愿、意志、决心”,本题表示决心,选B。,Goodbye!,
