Modal Verbs 情态动词 一、何谓“情态动词”？ 情态动词主要用来表示说话人的情感、态度等。 二、情态动词的特点 1.没有人称和数的变化(have to, have got to, be able to 除外) 2.有些情态动词有过去式的变化 e.g. will would , can could , may might , dare dared 3. 情态动词本身具有一定词义,但不能单独做谓语, 后一 般接动词原形一起构成谓语部分。 三、情态动词的否定形式 情态动词+ not +动词原形 can not: cant , must not: mustnt , need not : neednt一. can , could和be able to 1.can 1)“能” , 表示能力、技能 We can speak two languages. A computer cant think for itself.(不能)could 表 过去的能力 I could swim when I was only six. 表能力be able to 表能力，可用于各种时态, You will be able to skate after practising it several times. He hasnt been able to walk since his accident.还可表示成功地做了某事 = manage to do/succeed in doing sth. 此时只能用was/ were able to,不能用could The big fire spread quickly in the hotel but everyone was able to get out.1.You dont have to know the name of the author to find a book. You _ find the book by the title. must B. need C. can D. would 2.Just be patient. You_ expect the world to change so soon. cant B. neednt C. may not D. will notCA2) “可以”，表示许可(和may意思相近)常见于口 语 Can/May/Could (委婉语气)I come in? 我能进来吗? Can/May/Could (委婉语气) I smoke here? 我可以在这里抽烟吗？ -Can/ May/ Could (委婉语气) I use your pen? -Yes, you can. /you can (may) use my pen.Yes, you could. - No, you cant.3) “有时可能”在肯肯定句定句中，can可以表示一时的特定的可能 性/ 表理论上的可能性A clever person can make a mistake in his life. Children can be very naughty sometimes. It can be very hot in November in South China. 1. It is usually warm in my hometown in March, but it _ be rather cold sometimes. A. must B. can C. should D. wouldB2. Peter _ be really difficult at times even though hes a nice person in general. shall B. should C. can D. must 3.The World Wide Web is sometimes jokingly called the World Wide Wait because it _ be very slow. A. should B. must C. will D. canDC4) “可能”, 表推测/可能性,常用在疑问和否定句 中can be “can be “可能是可能是/可能在可能在” -Can the news be true? -It cant be true. What can he possibly mean? He cant be her father, for he is too young. can be doingcan be doing “ “可能正在做可能正在做” Can he be still sleeping? It is already ten oclock. cant/couldnt have donecant/couldnt have done “( (过去过去) )不可能做不可能做 过过” ” There cant/couldnt have been anyone in, for no one answered my phone. -Can Tom have stolen the money? -It must be Tom, only he knows where I put the money.1.You _ be hungry already-you had lunch only two hours ago! wouldnt B. cant C. mustnt D. neednt 2. There is no light on- they _ be at home. cant B. mustnt C. neednt D. shouldnt 3.She _ have left school, for her bike is still here. cant B. wouldnt C. shouldnt D. neednt 4.-Do you know where David is? I couldnt find him anywhere.-well, he _ have gone far- his coats still here. A. shouldnt B. mustnt C. cant D. wouldntAABCcould have done 用于虚拟语气 表 “（过去）本能够做却没有做”，暗含惋惜。 I could have passed my examination easily but I made too many stupid mistakes. -I stayed in a hotel. -Did you? You could have stayed in my bedroom.本能够 He did not regret saying what he did but felt that he _ it differently. could express B. would express C. could have expressed D. must have expressedCThank you for all your hard work last week. I dont think we _ it without you. can manage B. could have managed C. could manage D. can have managedB二. may和might 1)都表示允许或请求(might语气更委婉); “可以 ” You may watch TV now. You may take whatever you like. 我可以进来吗？-_I come in? 注意回答 -Yes, you may/can. No, you mustnt./youd better not. May/ Might /Can2)“也许”,都表示没有把握的推测(might指可能 性比may小,不表过去时态; 但也可表过去的可 能) He might be in the office.（可能性更小） -Are you coming to Jims party? -Im not sure, I may/might go to the concert. He was afraid that they might not come back soon.（过去的可能） She said that Tom might take her dictionary. I dont know whether John flew to New York or not, he might have flown to Paris. Dont eat the apples. It may have been gone bad.-excuse me, is this the right way to the Summer Place? -Sorry, I am not sure. But it _ be. A. might B. will C. must D. canA要表示很大可能性,可用 may/might well+v原 形 “很可能” What you said may/might well be true. 你说的很可能是真的。 The traffic is heavy these days. I _ arrive a bit late, so could you save me a place? A.can B. must C. will D. may Some people who dont like to talk much are not necessarily shy; they _ just be quite people. must B. may C. should D. would Liza _ well not want to go on the trip- she hates travelling. will B. can C. must D. may -where is my dictionary? I remember I put it here yesterday. -you _ it in the wrong place. A. must put B. should have put C. might put D. might have putDBDD3)表建议（和as well 连用）构成: may/ might as well+v原形,意为“不妨“,“倒不如 ” If that is the case, we may as well try. There is nothing more to do, so we may as well go home. You may as well stay where you are.4）用于虚拟语气：mi