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1、Unit 2Healthy eating Learning about Language,语法精讲探究学习,情态动词() 【情境探究,观察上面对话, 并类比填空。 1. Need he hand in the report today? No, he _. 2. Its too late. I _go home now,neednt,have to/must,要义详析】 情态动词, 通常无人称、时态变化, 只能对实义动词起到辅助作用, 与动词原形一起作谓语来表达语气意义。 1. ought to的用法 (1)表示出于义务、责任、道义等方面的要求而该做某事。 *To hand in the pa
2、per in time, we ought to have a busy schedule. 为了及时交上论文, 我们的日程应该紧一点。 *To build up our body, we ought to do enough exercise, such as running, swimming and hiking. 为了增强体质, 我们应该充分锻炼, 比如跑步、游泳和远足,2)表示说话人的猜测。 *She ought to succeed, because she tries hard enough. 她应该能成功, 因为她确实够努力的。 *The two teams are equal
3、 in ability, so the game between them ought to be a close one. 这两队能力相当, 因此他们之间的比赛应该是一场势均力敌的比赛,3)ought to的否定式是在ought后加not, 疑问式是将ought提前。 *If you make a promise you should keep it; you ought not to break a promise. 如果你做出了承诺, 你就应该遵守诺言, 不应该食言。 *Ought I to write to say thank you? 我应该写一封感谢信吗? Yes, I think
4、 you ought (to). 对, 我认为你应该写,即学活用】 句型转换。 (1)You ought to study harder than your brother. _than your brother? (变为疑问句) (2) I ought to ask you a thing like that. (变为否定句) I _you a thing like that,Ought you to study harder,ought not to ask,2. need的用法 need作情态动词时, 后跟动词原形, 表示“需要, 有必要”, 无人称和数的变化, 多用于否定句、疑问句或条
5、件句中。 *Need I send both Chinese and English CV (Curriculum Vitae) when applying? 在申请的时候, 我是不是需要发送中英文履历? *Whoever may say so, you need not believe it. 无论谁这么说, 你也不必相信它,名师点津】 (1)由need引导的一般疑问句的肯定回答常用must或 have to, 否定回答常用neednt。(2)need作实义动词时, 后可接名词、动名词、不定式等, 有人称、时态和数的变化,即学活用】 (1)Need I finish the work tod
6、ay? Yes, you _. /No, you _. 今天我需要干完这活吗? 是的, 必须干完。/不用, 你不必干完。 (2)Theres plenty of time. You _so fast. 时间很充足, 你不必开这么快,must,neednt,neednt drive,3. have to的用法 have to强调客观需要, 意为“不得不, 必须”, 后跟动词原形。口语中也常说have got to。它的特点是have有人称、时态的变化。 *I have to change the time for the lesson from morning to afternoon for
7、some reasons. (肯定句) 由于某些原因我不得不把上课时间由上午改到下午,2020天津高考)According to Professor Johnson, we dont have to read the book if we dont want to, as it is optional. (否定句) 根据Johnson教授所说, 如果我们不想读这本书的话可以不读, 因为它是选修的。 *Do you have to go? (疑问句) 你非得走吗,名师点津】must和have to的区别 (1)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
8、的看法, 即主观上的必要。 (2)在否定结构中: dont have to表示“不必”; mustnt表示“禁止,即学活用】 (1)句型转换。 We have to consider the question of where to sleep. _(疑问句) _(否定句) (2)(2018天津高考)Still we _and dream about whats at the top of our mountain. 我们仍然必须勇于攀登人生的巅峰并憧憬美好未来,Do we have to consider the question of where to sleep,We dont have
9、 to consider the question of where to sleep,must climb,4. dare的用法 dare表示“敢”, dare作情态动词时, 主要用于疑问句、否定句和条件状语从句中, 一般不用在肯定句中。 *The little girl dare not speak in public. 小女孩不敢在公众面前说话。 *She dare not go out alone at night. 她晚上不敢独自出门,即学活用】 (1)She _see you. 她不敢来见你。 (2) _to the boss? 你敢向老板说这种话吗,darent come to,
10、Dare you say that,5. 情态动词+have done (1)must have done表示对过去发生的动作或状态进行推测, 语气比较肯定, 通常只用于肯定句。 *Someone must have left the tap on, for the water was running over and flooding the bathroom. 一定是有人让水龙头开着, 因为水流得到处都是, 把卫生间淹了,2)may(might)have done表示对已发生的动作或存在的状态进行不肯定的推测, might的语气比may弱。主要用于肯定句或否定句。 *They say th
11、is suggests there may have been a land bridge between Africa and Europe at the time. 他们说这表明那个时候非洲和欧洲之间可能有一座陆地桥,3)can(could) have done表示对过去的某种情况的怀疑或不确定, 一般用于否定句和疑问句, could的语气较can弱。 *He cant have lost his way. I drew him a map. 他不可能迷路了。我给他画了一张地图。 (4)ought to(should)have done表示过去本应该做某事但没做, 其否定式表示过去不该做某
12、事但做了。 *You ought not to have made fun of him, and you should have learned from him. 你本不应该取笑他的, 你本应该向他学习,5)neednt have done表示过去做了不必做的事情。 *We need not have worried about the math exam. It was a piece of cake. 我们本不必担心数学考试, 实际上它很容易。 (6)would like/love to have done sth. 表示“本打算/本想”。 *I would like to have
13、read the article, but I was very busy then. 我本打算读这篇文章的, 但是当时我太忙了,7)could have done是虚拟语气, 表示对过去发生的事情的假设, 意思是本来能够做某事而实际上没有做。 *(2020全国卷)Rather than getting caught up in how you could have done better, why not offer yourself a compassionate response. 与其纠结自己本可以做得更好, 为什么不给自己一个富有同情心的回答呢,即学活用】用适当的情态动词填空。 (1
14、)They _ have been to the Great Wall, havent they? (2)He _ have watched TV last night, for he knew he would have a test. (3)With a little care you _ have avoided the mishap. (4)You _have done more exercise before. (5)I _ have cooked so much food. Nobody was hungry,must,cant/couldnt,could,should/ought
15、 to,neednt,课时检测素养达标,选择适当的情态动词填空 1. As middle school students, we _learn from the real heroes. (have to/ought to) 2. You _ take an umbrella. It isnt going to rain. Well, I dont know. It may do. (darent/neednt) 3. He _ have missed the train; he arrived at the train station two hours early. (cant /mustnt,ought to,neednt,cant,4. I _ help her because she is in trouble. (should/need) 5. They _stay in the office last night because of the snowstorm. (have to /must) 6. They argued all the time and thought it _ be good for the
