2017届高考英语二轮语法专题课件：专题6 情态动词

　　考点透析 知识清单 考点警示

　　情态动词在最近几年的高考语法填空中还没有直接考查过，但这并不意味着今后也不会考。另外，熟练掌握情态动词的用法，对准确理解语法填空、完形填空、阅读理解、听力理解中含有情态动词的句子是很有益处的，在写作中也可能会用到情态动词，因此，我们应当学好情态动词。尤其要掌握好常用情态动词的用法。　 一、9大情态动词的基本用法 情态动词 主要用法 典句例示 can/could 表示能力 He can play table tennis quite well. 表示理论上的可能性，“有时候可能会” Even an experienced teacher can make mistakes. 表示请求和允许 表示请求，口语中常用could代替can ①You can have my seat.I'm going now. ②Could you give me a hand？ may/might 表示请求、允许、许可，might比may的语气更委婉 ①You may use my dictionary.

　　②Might I have a look at your new computer？ must 表示“必须；应该” We must study hard and make progress every day. 表示“偏要，硬要”做某事 If you must smoke，please go out. 情态 动词 主要用法 典句例示 shall 用于第一、三人称的疑问句中，表示征求对方的意见 Shall I open the door？ 用于第二、三人称的陈述句，表示说话人给对方的命令、警告、允诺或威胁；此外，当颁布法律、规定时也用shall ①You shall get an answer from me by tomorrow.

　　②He shall go first，whether he wants or not. ③This law shall come into effect on May lst. should 表示劝告和建议，作“应该”讲 You should learn from each other. 表示惊讶、意外等情绪，意为“竟然” I can't bear that he should speak ill of me. 用在if条件句中，表示可能性很小，但也不是完全不可能 If anyone should come，say I'm not at home. 情态动词 主要用法 典句例示 will/ would 用于表示意志或意愿 I have told him again and again to stop smoking，but he will not listen. 表示“请求；建议”。用would比will委婉、客气些 Would you like some more coffee？ 表示习惯：will可以表示现在的习惯，意为“总是；习惯于”。表示过去的习惯性动作用would ①She will sit for hours reading in the afternoon.

　　②When he was young，he would listen to music alone in his room. 表示事物的某种性质和倾向 Wood will float on the water. need 表示“需要；必要”，用于否定句、疑问句和条件从句中 —Need we take the test？—No，we needn't. dare 表示“敢；敢于”，主要用于疑问句、否定句和条件从句中，一般不用于肯定句。I dare say是习惯说法，意为“我想，大概” How dare you talk like that？ ought to 表示义务，意为“应当”，语气比should强，表示不十分肯定或含蓄的推测，意为“应是，应该 ” ①Everyone ought to obey the traffic regulations. ②He ought to be home by now. 二、3组易混情态动词用法比较 情态动词 主要用法 典句例示 can(could)/ be able to can/ Could can只有现在式和过去式could，表示一般能力 I am starving to death.I can eat two bowls of rice. be able to 有更多的形式，was/were able to表示通过努力、克服困难做成某事 The fire spread through the hotel very quickly but everyone was able to get out. must/have to must 侧重表示说话人的主观看法；只有一种形式 We must rely on ourselves. have to 表示客观需要，有不同的形式 I have to give it up because of my illness. would/ used to would 表示过去习惯性或重复性的动作，没有与现在对比的含义，不可用于无人称句或存在句 Last year，our English teacher would sometimes tell stories after class. used to 表示过去经常发生的动作或存在的状态，强调今昔对比，可用于无人称句或存在句 He told us he used to play football when he was young. 考点警示 (1)can的一些常用固定搭配cannot but do sth/cannot help but do sth/cannot choose but do sth表示“不得不，只好” cannot/can never...enough/too再……也不为过 (2)may的一些常用固定搭配 may well＋动词原形意为“完全能，很可能”，may as well＋动词原形意为“最好，满可以，倒不如” (3)mustn't表示“禁止”“不许做某事” 回答用need提问的问句时与回答用must提问的问句时一样，肯定回答用must，否定回答要用needn't或don't have to。 ①I cannot choose but go.

　　我只好去。 ②You cannot be careful enough. 你再细心也不为过。 ③Her appearance has changed so much that you may well not recognize her. 她的模样变化太大，你很可能认不出她了。 ④You may as well do it at once. 你最好马上就做这件事。 三、5大表示推测的情态动词用法比较 情态 动词 适用句式 适用时态 意　义 典句例示 must 肯定句 一般时、进行时、完成时 一定、肯定 ①You must be hungry after the long walk.

　　②He must be sleeping in the dormitory. can(could) 疑问句，否定句 一般时、进行时、完成时 可能，能够 ①She can't be reading in the reading room now.

　　②Can/Could this be an excuse for that？ may(might) 肯定句，否定句 一般时、进行时、完成时 也许，可能 ①He may not be happy.

　　②He may be playing basketball on the playground. should(ought to) 肯定句 一般时 确定或期待，“应该” ①He should be around sixty years old.(确定) ②It's nearly seven o'clock.Jack should be here at the moment.(期待) will(would) 肯定句、否定句、疑问句 一般时、进行时、完成时 大概 ①He will have forgotten me.I left him 18 years ago.

　　②It would be about ten when he left home. 四、“情态动词＋have done”用法 类型 构成 用法 句式 典句例示 对过 去的 推测 must have done 表示对过去已经发生的行为进行推测，意为“想必/准是/一定做了某事”。 肯定 You must have gone to bed late last night.Your eyes are red. can/could have done 表示对过去发生的行为的怀疑和不肯定 否定、疑问 He cannot have forgotten it. may/might have done 表示对过去已发生的行为的推测，意为“也许/或许/已经(没有)……”。 肯定、否定 It's too late.I think he may have gone to bed. 类型 构成 用法 句式 典句例示 表示 后悔、 责备 或遗憾 could have done 表示过去没有实现的可能性，意为“本来可以……” 肯定 The accident could have been avoided. should/ought to have done 表示本该做某事而实际上未做 肯定、否定 You are late.You ought to have arrived five minutes earlier. needn't have done 表示做了本来不必做的事 否定 I actually needn't have bought so much wine—only three people came. had better have done 用于事后的建议，含轻微责备的口吻，意为“当时最好做了某事” 肯定、否定 You had better have started earlier. would rather have done 表示“当时宁愿做了某事” 肯定、否定 I would rather have taken his advice. 1．情态动词不能单独作谓语，必须与其它动词一起作谓语。另外，(1)后面接动词原形。(2)没有人称和数的变化。(3)变为疑问句或否定句时不需要加助动词，而是将情态动词移至主语前变为疑问句，在情态动词后加not，构成否定句。 2．掌握一些有关情态动词的常用句型，在语法填空题中极易考查到。如：cannot...too无论怎样……也不过分，You cannot be too careful while driving.开车时你越小心越好。

　　cannot wait to do迫不及待地做

　　He couldn't wait to see the film.

　　他非常渴望看这部电影。 cannot(help)but do不得不做，只好做 She couldn't but agree to my idea. 她只好同意我的想法。 cannot help it没有办法 cannot help doing情不自禁地做 may well有充分的理由可以 You may well be proud of him. 你有足够的理由为他骄傲。 may/might as well最好，不妨。 3．个别情态动词的特殊用法

　　(1)must可以转化为名词，意思是“必需的东西”，如：

　　Comfortable shoes are a must when going hiking in the mountains.

　　去山路远足时，舒适的鞋子是必需的。

　　(2)行为动词need，dare有人称和数的变化，后接名词、代词、动词不定式，动词v.­ing形式及复合宾语，如

　　The question needs to be discussed＝The question needs discussing.