高三英语语法专题课件：情态动词和虚拟语气.ppt

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1、高三英语语法专题课高三英语语法专题课件：情态动词和虚拟件：情态动词和虚拟语气语气 考点要览考点要览情态动词在一般疑问句中的问与答“情态动词+不定式完成式”的结构和用法“情态动词+be doing”的意义“情态动词+have been doing”的意义情态动词shall与will, could表意愿时用法区别含情态动词must的句子的反意疑问句构成虚拟语气在其它从句中的用法及几种特殊句型疑难点击疑难点击部分情态动词的问与答 “情态动词+不定式完成式”结构及意义 “情态动词+be doing”的意义 “情态动词+have been doing”的意义 情态动词shall, will和would表

2、意愿时用法区别 dare与need, used to与would用法及区别 must和have to用法区别 含有must句子的反意疑问句构成 虚拟语气在if引导的条件状语从句中的用法 虚拟语气在名词性从句中的用法 几种常用的虚拟语气结构 (1) Need I? Yes, you must. No, you neednt.(2) Must I? Yes, you must. No, you neednt.(3) May I? Yes, you may. (=Yes, certainly/of course.) No, you may not. (=No, you cant/mustnt.)(4

3、) Shall I.? Yes, please. No, thanks. No, you neednt. （委婉） No, you cant. （反对） No, you mustnt. （禁止）(5) Might I? Yes, you can. No, you cant.(1)must have done （语气肯定）“过去一定” 表示对过去情况极大把握的推测。I didnt hear the telephone, I must have been asleep. 我没有听到电话铃声，我一定是睡着了。(2) should/ought to have done “本来应该”“按理该”表示责备，

4、惋惜。The plant is dead, I should have given it more water. 植物死掉了，我本应该给它浇更多的水的。(3) may/might have done （语气不肯定） “过去可能”表推测。 He might have given you more help, even though he was very busy.他本应可以给你更多帮助，即使他非常忙。(4) cant/couldnt have done （语气肯定） （否定句和疑问句）“过去不可能” 对过去发生的事的不肯定或怀疑。 He cant have studied English be

5、 fore. 他以前没有学过英语。(5) could have done 本来能做却未做，表责备。 might have done 本来可以做却未做，表责备。 He could have walked to the station, it was so far.我们本应走着去火车站，这么近。 (6) neednt have done 已做了某事，但没有必要。 shouldnt have done oughtnt to have done 本来不该做却做了， 表责备，惋惜。 I neednt have bought the book. 我没有必要买这本书。 Tom ought not to ha

6、ve told me your secret. 汤姆本不该把你的秘密告诉我。 “情态动词+be doing”表推测，“应当正在可能正在”。 They must be waiting for you. 他们一定在等你。（1）间或此结构可表示“即得，将要”这类意思。 I must be leaving now. 我得立刻离开了。（2）间或表示老是在做某事。 Why must you always be finding fault with that girl? 你为什么总是和这姑娘过不去？“情态动词情态动词+have been doing”表推测有“应当一直在”等含义。例: They cant h

7、ave been working for that long last night. 昨晚他们不可能工作那么久。 Your mother must have been looking for you. 你妈妈一定一直在找你。询问对方意愿意愿，表白说话人的意愿。 向对方提出请求时（第二人称）用will/would。 当shall用于第三人称疑问句时， 表示征求对方意见或请求指示。dare和和need作情态动词时不用于肯定句；作实义动词时不受限制。used to 表示“过去常干”，但现在不干了，常与like, be等状态动词连用。would (do)表示“过去常干”，但不强调现在如何，并带有赞扬、

8、厌恶等感情色彩。must表示说话人的主观看法，而have to表示客观的需要；mustnt表示为“决不能”“禁止”“一定不要”，而dont have to表示“不必要”。（英国英语中常用neednt）（1）must表示“必要”“必须”时，附加部分用mustnt?或者说neednt?（2）must用于否定形式mustnt时，附加问句部分用may或must。（3）must表示“推测”意义时，要根据具体情况而确定。例如：He must know the secret, doesnt he?他一定知道这个秘密，不是吗？He must be a teacher, isnt he?他一定是个老师，不是吗？

9、You must have seen him off yesterday, didnt you?你昨天一定是看见他离开了，不是吗?You must have studied English before, havent you?你以前一定是学过英语，不是吗？（1）若与现在事实相反 从句形式为：If+主语+动词过去式（be动词一般为were） 主句形式为： 主语+would/should/could/might +v.（2）若与过去事实相反 从句形式为：If+主语+had+ done 主句形式为： 主语+would/should/could/might+ have+done （3）若与将来事实相

10、反 从句形式为： If+ 主语+ 动词过去式 should + v. were to + v. 主句形式为：主语+would/should/could/might + v. （1）在某些动词的宾语从句中， 形式是“（should）+动词原形”。常见动词有：一个坚持（insist）；两个命令（order, demand）；三个建议（advise, suggest, propose）；四项要求（demand, require, request, ask）。 （2）作某些词的同位语和表语从句时，形式是：“（should）+动词原形”。常见的名词有：advice, idea, order, deman

11、d, plan, proposal, suggestion, request, opinion等。 （3）下列主语从句中用“（should）+动词原形”It is necessary (important, natural, strange, surprising, etc) thatIt is a pity (a shame, no wonder etc ) thatIt is suggested (decided, ordered, requested, etc) that （1）用but for, without等介词短语表达条件。例如： But for you, we couldnt

12、have carried out the plan. 要不是你的话我们（当时）无法实行那项计划。 （2）Its time that + 动词过去式 should+动词原形 “该做的时候了” 例如： It is time we got up .该是起床的时间了It is (high) time we should get up.该是我起床的时间了 （3）would rather (that)动词过去式（与现在或将来相反） had + done了“宁愿（而不）”（与过去事实相反）例如：I would rather he stayed at home now.我宁愿他现在在家里 he stayed

13、at home tomorrow.我宁愿他明天在家里. he had stayed at home yesterday. 我宁愿他昨天在家里( 4 ) wish=if only+从句（从句谓语动词有三种形式） would (could, might) +动词原形（与过去事实相反） 动词过去式（与现在事实相反） had+过去分词或用could have+ 过去分词（与过去事实相反） 例如： I wish (ed) I could (would, might) go to the moon in a spaceship one day. 我希望有一天我能乘坐宇宙飞船登上月球. I wish (=I

14、f only) he visited us now. 要是他现在能来看望我. I wish (If only) he had visited us last night. =I wish (If only) he could have visited us last night. 要是他昨晚能来看望我们就好了. (5) as if (thought) （方式）“好像，仿佛” + 动词过去式（与现在事实相反） 过去进行式（与现在正在进行相反） had+done（与过去事实相反） could/might/would+动词原形（与将来事实相反）例如： It looks as if/though so

15、meone were running. 好象有人在跑步. she hadnt done that. 她好象没有做那样的事 she were two years younger today. 她今天看起来好象年轻了两岁. she would live another 100 years. 她好象还能活100岁.（6）有时候，条件从句表示的动作和主句表示的动作发生的时间是不一致的（如一个是过去发生的，一个是现在发生的），这这时动词的形式要根据表示的时间来调整。例如： If I had followed the doctors advice, I would be better now. 如果我听了

16、医生的建议,我现在可能就好多了. If you had worked hard then, you would be in the university now. 如果那时你努力一些,你现在就上大学了. If the doctor had come sooner last night, the patient would be alive now. 如果医生昨晚能早来一会儿,病人现在可能就活下来了.（7）even if/though 引导让步状语从句，从句中用may/might+动词原形，may或might可省略，表示与现在情况相反；从句用过去时，表示与过去情况相反；类似的词还有：though

17、/as though/so long as/no mattermatter wh-/whatever/whenever/whoever等。 However dangerous it might be, he would have a try. 无论多危险，他都要试一试。 Even though I had been very busy then, I would have helped you. 即使我当时很忙，我还是会帮助你的。 （8）表示祝愿或诅咒的祈使句 May you succeed! 祝你成功！ God bless you! 愿上帝保佑你！ （9）过去分词短语表示条件 Given m

18、ore time, we could have done it better. 倘若给我们会把它做得更好。 （10）通过上下文表示条件 Such mistaken could have been avoided. 这种错误本来是可以避免的。1.Excuse me, but I want to use your computer to type a report. You _ have my computer if you dont take care of it. A. shant B. might not C. neednt D. shouldnt2. Excuse me. Is this

19、the right way to the Summer Palace? Sorry, I am not sure. But it _ be. A. might B. will C. must D. can3. Ill tell Mary about her new job tomorrow. You _ her last week. A. ought to tell B. would have told C. must tell D. should have told4. I heard they went skiing in the mountains last winter. It _ t

20、rue because there was little snow there. A. may not be B. wont be C. couldnt be D. mustnt be5. He hesitated for a moment before kicking the ball, otherwise he _ a goal. A. had scored B. scored C. would scored D. would have scored6. Write to me when you get home. _. A. I must B. I should C. I will D.

21、 I can7. I hear youve got a set of valuable Australian coins. _ I have a look? Yes, certainly. A. Do B. May C. Shall D. Should8. What would have happened _, as far as the river bank? A. Bob had walked farther B. if Bob should walk farther C. had Bob walked farther D. if Bob walked farther9. Sorry, I

22、m late. I _ have turned off the alarm clock and gone back to sleep again. A. might B. should C. can D. will10. _ be sent to work there? A. Who do you suggest B. Who do you suggest that should C. Do you suggest who should D. Do you suggest whom should11. With better equipment, we _ the job even soone

23、r. A. would finish B. might finish C. could have finished D. had finished12. _ the fog, we should have reached our school. A. Because of B. In spite of C. In case of D. But for13. The young man insisted that he _ nothing wrong and _ free. A. did; set B. had done; should be set C. do; be set D. had d

24、one; must be set14. They must have here the day before yesterday, _? A. mustnt they B. werent they C. havent they D. had they15. Do you still remember the day when we went to the Great Wall? I cant remember it well, but _ sometime last autumn? A. might it be B. could it have been C. could it be D. must it have been