,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,助动词与情态动词：,助动词,be,、,have,和,do,情态动词,can,、,may,、,must,的用法情态动词的其他形式,1.Be,动词的用法,(1),助动词,be,和现在分词一起构成进行时或完成进行时。如,:,He is reading.,他在读书。,Ill be waiting for you there then.,我到时在那儿等你。,(2),助动词,be,和过去分词一起构成被动语态。如,:,Is he taken good care of?,他被照顾得好吗,?,They shall be punished.,他们一定要受惩罚的。,(3),助动词,be,用作系动词。如,:,Matthew is a teacher.,马修是个老师。,We were late today.,我们今天退到了。,(4),助动词,be,和不定式连用，可以表示下面几种情况。,表计划，只用于肯定句和疑问句。如,:,We are to discuss it the following week.,我们打算下周讨论那件事。,When is the wedding to be?,婚礼什么时候举行,?,表命令，只用于肯定句和否定句。如,:,All junior officers are to report to the colonel at once.,全体下级军官都必须立即向上校报到。,Tom says I am to leave you alone.,汤姆要我不理会你。,表可能，多用于被动结构。如,:,Her father was often to be seen in the bar of this hotel.,在这家旅馆的酒吧经常可见到她父亲。,Where is he to be found?,在哪儿可找到他,?,表示“必须”，“应该”多用于现在式。如,:,Nobody is to leave this room.,谁也不许离开这个房间。,What am I to do next?,下一步我该做什么,?,Hes to blame.,该怪他。,表注定，多用于过去式。如,:,He was to be my teacher and friend for many years to come.,在后来许多年里他是我的老师和朋友。,The professor did not know at the time that he was never to see his native place again.,当时教授不知道他再也见不到他的故土了。,(5),助动词,be,用于条件从句。如,:,If we are to succeed,we must redouble our efforts.,我们要想成功，必须加倍努力才行。,(are to,意为“想要”,),(6)be,后接,going to,about to,on the point of,等表示将来时间或根据计划、意图等将要发生的事。如,:,Its going to rain.,快要下雨了。（将来时间,),Hes about to leave.,他正要走。,(,将来时间,),2.Have,的用法,(1),助动词,have,与过去分词一起构成各种完成时态。如,:,I have read the book.,我读过这本书。,Kenny has left.,肯尼已经走,7,。,(2),助动词,have,与,been+,现在分词构成各种完成进行时态。如,:,I have been washing the clothes the whole morning.,整个上午我都在洗衣服。,Lambert has been working as a worker here for nearly five years.,兰伯特一直在这里当工人，几乎有五年了。,(3),助动词,have,构成,had better,had best,had rather,等词组。,Had better,和,had best,是“最好还是,”,或“还是,好”的意思。在,had better,中，,had,不表示过去时间，不能用,have,或,has,代替。,Had better,后可接不带,to,的不定式或接进行式、完成式或被动语态。,had better,的否定式是,had better not,。如,:,You had better stay at home.,你最好呆在家里。,Youd better have had that experience before.,假如你以前有过那个经验就好了。,Youd better not run the risk.,你最好不要冒那个险。,(4),补充,Have,还可用作使役动词和实义动词,(,表示“有”，“吃”等意义,),。如,:,They have had the problem solved.,他们让其他人解决了这个问题。（使役动词,),Bad news has wings.,丑事传千里。,(,实义动词,),What shall we have for lunch?,我们午饭吃甚么,?(,实义动词,),3.Do,的用法,(1),助动词,do,does,和,did,用于构成否定句、疑问句和倒装句。如,:,Do you understand all this?,你明白这一切吗,?,Dont go yet.,先别走。,(2),助动词,do,does,和,did,用于代替句中的主要动词，以避免重复。如,:,He didnt go to the party.Neither did I.,他没有去参加晚会了我也没有去。,I do not agree.Nor does he.,我不同意，他也不同意。,(3),用于加强语气，,do,does,和,did,位于陈述句的动词原形前，,do,位于祈使句中的动词原形前。如,:,Do have another cup of coffee before you go.,走前请一定再喝一杯咖啡。,Thats exactly what he did say.,他就是那样说的。,But I do want to go.,可是我确实想去。,(4),在一些以否定副词如,never,rarely,scarcely,only,等为首的句子中，如果实义动词是现在时或过去时，助动词,do,和,did,可以构成主谓倒装。,如,:,Never did I tell him about that.,我从来没有告诉过他那件事。,Rarely does it snow in the South.,南方很少下雪。,情态动词,can.may.must,的用法,1.can,的用法,2.could,的用法,3.may,的用法,4.might,的用法,5.must,的用法,1.can,的用法,(1)can,表示主语的能力。如,:,The hall can seat 1,000 people.,这个大厅能坐,1 000,人。,Can you play the piano?,你会弹钢琴吗,?,(2)can,表示说话人的猜测,(,即可能性,),，多用于否定句和疑问句。如,:,Can it be true?,这能是真的吗,?,The moon cant always be at the full.,月不可能总是圆的。,What can she mean?,她可能是什么意思呢,?,(3)can,表示许可。如,:,下,his sort of thing cant go on.,这样的事不能再继续下去,7,。,You cant smoke here.,你不可在这里吸烟。,(4)can+,完成式 表示说话人对过去情况的猜测,(,只用于否定和疑问结构中,),。如,:,He cant have missed the way.I explained the route carefully and drew him a map.,他不会迷路。我对他详细说明了路线，还画了一张地图。,Can the team have left already?,球队已经离开了吗,?,2.could,的用法,(1)could,表示主语的能力，为,can,的过去时形式，如,:,Daisy couldnt come yesterday because she was ill.,戴西昨天不能来是因为她病了。,They said they could swim.,他们说他们会游泳。,(2)could,表示说话人的猜测,(,即可能性,),。如,:,He could be right.,他或许是对的。,Could it be Henry?,可能是亨利吗,?,At that time we thought the story could not be true.,那时我们认为所说的事不可能是真的。,(3)could,表示许可。如,:,Father said I could swim in the river.,爸爸说我可以在河里游泳。,Could I help you?,我能帮忙吗,?(,比,Can I help you?,婉转,),The man asked if he could smoke in the hall.,那个人问可不可以在大厅里吸烟。,(4)could+,完成式 用于肯定句时一般表示过去可能完成却未完成的动作。如,:,I could have reported you.,我本可以报告你的。,You could have let me know earlier.,你本来该早一些告诉我。,3.may,的用法,(1)may,表示许可，多用于肯定句和疑问句中，否定句中不常用。如,:,May I ask you a question?,我可以问你个问题吗,?(,比,Can I ask you a question?,更礼貌,),You may keep the book for two weeks.,这本书你可以借两周。,(2)may,表示可能性，常用于肯定句和否定句中，指现在或将来的可能性。如,:,It may be true.,那可能是真的。,The road may be blocked.,这条路可能不通了。,(3)“may+,完成式”表示说话人对过去情况的猜测。如：,Eva may have missed her train.,伊娃可能误火车了。,He may have read the book.,他可能读过这本书。,(4)may as well(=might as well),是一个习语，作“不妨”或“完全有理由”或“还是,的”解，用于提出建议。如,:,You may as well stay where you are.,你还是原地呆着好。,All the pubs are closing.We may as well go home.,所有的酒馆都打烊了。我们还是回家吧。,在对由,may,引出的“请求许可”的问句做出肯定回答时了通常不用过于严肃和正式的,Yes,you may.,而多用,Yes,please?(,请便,),或,Of course/Certainly(,当然可以,),；否定回答时，常用“,Please dont(,请不要,).”,或“,No,you mustnt(,不行,).”,4.might,的用法,(1)might,表示许可。如,:,Might I have a word with you?,我可以同你说句话吗,?,Might I make a suggestion?,我可以提一项建议吗,?,Might we ask you a,favour,?,我们可以请你帮个忙吗,?,但要注意,:Might I,比,May I,更客气，但是不如,May I,常用。,(2)might,表示说话人的猜测，其把握性比,may,小。如,:,