北师大版高中英语选修七Unit21 Human Biology语法篇教师版

1、Unit21 Human Biology-语法篇_1、掌握混合条件句中的虚拟语气的用法。2、情态动词的用法。混合条件句中的虚拟语气混合条件句主句是指条件句中含有不同的条件结构，谓语动词所表示的动作和条件从句谓语动词所表示的动作并不是同时发生,如一个与过去事实相反，另一个与现在事实相反。在这种条件句中， 动词的形式要根据具体情况进行调整。非真空条件从句主句If it had rained last night,it would be very cold today.If I had taken your advice,I would have no trouble with the work n

2、ow.If I were you,I would have gone to see the film last night.If he had told me about it, I would known what to do nowIf you had followed the doctors advice (then), you would be all right now.如果你那时听了医生的话,你现在就好了.(主句与从句发生的时间不同,应按照主句与从句各自的时间做调整.)If you had watered them more, the crops would be growing

3、still better.如果你再给庄稼多浇些水,他们会长得更好.(指现在长得更好.)If you had watered them more, the crops would have grown still better.如果你早就给庄稼多浇些水,他们就会长得更好(表示对过去的虚拟)情态动词一定义情态动词是一种本身有一定的词义,但要与动词原形一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。情态动词后面加动词原形。二分类： 情态动词有四类： 做情态动词：must,can(could),may(might),ought to 可做情态动词又可

4、做实义动词：need,dare 可做情态动词又可做助动词：shall(should),will(would) 具有情态动词特征：have(had) to,used to三常用情态动词的用法1.must和have to表示必要性2.cant表示不可能， mustnt表示不允许或禁止3.dont have to和neednt表示没有必要4.can 和could 表示能力和可能性， 还可表示请求允许5.must,might,could表示猜想和推测6.may表示可能和允许四情态动词+have+过去分词1. “must+have+done”表示对过去事情的肯定推测，译成“一定做过某事”，该结构只用于肯

5、定句。 1). It must have rained last night, for the ground is wet. 昨晚一定下雨了，因为地面还是湿的。 2). You must have been mad to speak to the servant. 你和仆人说话，一定是发疯了。 2. “cant+have+done”表示对过去事情的否定推测，译成“不可能做过某事”。 1). Mr. Smith cant have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了，我刚才还在图书馆见过他。 2

6、). Mary can't have stolen your money. She has gone home. 玛丽不可能偷你的钱，她回家去了。 3. “can+have+done”表示对过去行为的怀疑，用于疑问句，译成“可能做过吗？”。 1). There is no light in the room. Can they have gone out? 屋里没有灯，他们可能出去了吗？ 2). There is nowhere to find them. Where can they have gone? 到处找不到他们，他们可能到什么地方去呢？ 4. “could+have+don

7、e”是虚拟语气，表示对过去事情的假设，意思是本来能够做某事而没有做。 He could have passed the exam, but he was too careless. 本来他能够通过考试，但是他太粗心。 5. “may+have+done”表示对发生过去的事情的推测，意思是“可能已经”或“也许已经”，用于肯定句中。 What has happened to George? I don't know. He may have got lost. 乔治发生了什么事？我不知道，他可能迷路了。 “might+have+done”表示对过去事情的推测，might与may意思相同，但

8、可能性更小。多用于虚拟语气结构中。 1). He might have given you more help, even though he was busy. (MET90) 他或许会多给你一些帮助，即使他很忙。 2). She might have achieved greater progress, if you had given her more chances. 如果你多给她点机会，她可能已经取得更大的成绩。 6.“should+have+done”意思是“本来应该做某事，而实际没做。” “shouldn't+have+done”表示本来不应该做某事，而实际做了。含有指责

9、对方或自责的含意。 1). Tom, you are too lazy. The work should have been finished yesterday. 汤姆，你太懒惰了，这项工作本来应该昨天就做完的。 2). Look, Tom is crying. I shouldn't have been so harsh on him. 看，汤姆哭了，我本来不应该对他如此严厉。 7. “ought to+have+done”表示过去应该做而实际并没有做，译成“理应做”，往往表示遗憾。与“should+have+done”用法基本一样。例1. (2019北京)Cant you sta

10、y a little longer?Its getting late. I really _go now, My daughter is home alone.A .may B .can C . must D .dare 解析：考查情态动词辨析。句意：你不能再多待会儿吗?很晚了，我必须得走了。我女儿一个人在家。may可能，可以，也许；can能，会；must必须，必然要，必定会； dare敢，胆敢。结合句意，故选must。故可知本题答案。答案：C例2. (2019重庆) You_ be Carol. You havent changed a bit after all these years.A

11、. must B. can C. will D. shall解析：本题考查情态动词。句意：你肯定是卡罗，这些年你一点也没有变化。must表示对现在的肯定推测。 故选A。 答案：A 例3. (2019安徽安庆一中月考) If you were older I _ you to go there yesterday.A .will allow B. should allow C. would have allowed D. had allowed解析：从句是对现在的虚拟，而主句是对过去的虚拟，所以主句中要用“would/ should/ might/ could + have + 过去分词”由此可

12、知本题答案。 答案：C例4. (2019北京海淀二模) If I _the project earlier, I would be enjoying myself on the beach now. A. might finish B. finished C. had finished D. would have finished解析：句意：如果我能早此完成这个项目，我现在就在沙滩上享受了。本题混合条件句中虚拟语气。if引导的从句是对过去事实进行的虚拟。应用had finished。由此可知本题答案。答案：C例5. (2019北京海淀一模)What do you think of the Hu

13、awei P7?Terrific. I would buy one if I _ an iPhone 6 Plus last year. A. didnt buy B. dont buy C. hadnt bought D. havent bought解析：句意：你觉得华为P7怎么样？太棒了。如果去年我没有买iPhone 6 Plus的话，我就买一个华为P7。本题考查if引导的虚拟语气的用法。根据语境可知，此处为混合虚拟语气，if引导的条件从句是对过去发生的事情进行虚拟。根据语境可知本题答案。答案：C 基础演练一单项选择。( )1.Marys sister looks very be

14、autiful now. But she was very ugly before she tidied up her appearance(整容). You _believe it! A. shouldnt B. mustnt C. wouldnt D. might not ( )2.Where is Mr. Smith? I cant find him anywhere. He _far, for his mobile phone is still here. A. mustnt have gone B. wouldnt have gone C. cant have gone D. sho

15、uldnt have gone ( )3.Why didnt John take part in the race yesterday? He _out of the race because of his serious injury. A. neednt have dropped B. should have dropped C. would have dropped D. must have dropped ( )4. You _the day off from work, which created a burden for everyone else. A. shouldnt hav

16、e taken B. mustnt have taken C. couldnt have taken D. wouldnt have taken ( )5. More water and the young trees_. A. couldnt have died B. neednt have died C. shouldnt have died D. mustnt have died( )6. Although Lily is usually easy-going, she _be sometimes quite annoying. A. must B. need C. can D. sho

17、uld ( )7. “Nothing in this letter _be considered as a license to use the artists personal possessions”, the judge declared on the court. A. can B. shall C. must D. may ( )8. May I take this book out of the reading room? No, you_. You read it here. A. mustnt B. mightnt C. wont D. neednt ( )9. Mr. Smi

18、th, Tom is here._ he come in now? Oh, yes please. Ive been expecting him. A. Should B. Shall C. Might D. Must ( )10.Why dont you wear your jogging shorts, Mum? Well, my legs are too skinny, if you_know. A. should B. can C. need D. must Keys: 1.【解析】选C。考查情态动词表示推测。句意: 玛丽的姐姐现在看上去非常漂亮。但是她在整容前是非常丑陋的。你不会相信

19、这事情。根据语境“前后丑、漂亮”的对比, 推知人们“不愿意; 不会”相信; wouldnt意思为“不情愿”符合题意。 2.【解析】选C。考查情态动词表示推测。句意: 史密斯先生在哪里? 我到处找不到他。他不可能走远, 因为他的手机还在这里。根据语境“到处找不到他”推知是对过去情况的猜测, 故cant have gone far意思为“不可能走远”符合语境。 3.【解析】选D。考查情态动词表示推测。句意: 约翰昨天为什么没有参加比赛? 他因为受伤严重肯定退出比赛了。由此处语境“受伤严重”推知对于“退出比赛”的推测语气比较强烈, 有“肯定”之意, 并且是对过去情况的推测故用must+have do

20、ne形式。 4.【解析】选A。考查情态动词的用法。句意: 你不应该休班, 这给其他所有的人都造成了负担。由句子语境分析, 句子谓语动作发生在过去, “过去不应该做某事”要用shouldnt have done, 故选A。must表示推测意义不可用于否定形式, 故B项不存在; couldnt have done不可能做某事; wouldnt have done过去不会做某事。 5. 【解析】选A。考查情态动词表推测。句意: 多浇一点水, 小树苗就不会死了。根据句意可知是对过去事情的推测。couldnt have done指过去肯定不会做某事; neednt have done表示没必要做某事但做

21、了; shouldnt have done表示本不应该做某事但做了。根据句意可知选A项。 6. 【解析】选C。考查情态动词表示推测。句意: 尽管Lily通常很随和, 但有时也相当讨厌。can意思为“有时会”符合题意。 7. 【解析】选B。考查情态动词表示允许。句意: 法官在法庭上宣布: “在这封信里使用艺术家的个人财产不会考虑在内。”根据语境此处为“不允许”, shall用在二、三人称的陈述句中表示“允诺”符合语境。中国教育出版网 8. 【解析】选A。考查情态动词表示允许。句意: 我可以把这本书带出阅览室吗? 不, 不可以。你要在这里阅读。根据may的问句语气, 此处对may的请求作了否定回答

22、, 意思为“不可以; 不允许; 禁止”, 故答案A合适。 9. 【解析】选B。考查情态动词表示请求。句意: 史密斯先生, 汤姆在这里。他现在可以进来吗? 噢, 是的。我一直等着他呢。根据语境“来了; 一直在等”推知“没有进来”, 此处“征求进来”的同意。shall用在一、三人称的句子中表示请求。 10. 【解析】选D。考查情态动词表示警告。句意: 妈妈, 你为什么没有穿你的慢跑短裤呢?如果你非要知道的话, 我告诉你, 我的腿太瘦。根据语境“告诉了不穿慢跑短裤”的原因, 推知“非要; 一定”想知道的迫切心情, 故答案D合适。巩固提高二单句改错1. The 5-year-old girl wish

23、es she is a college student now._2. He suggested that we took more exercise to keep fit._3. I know people are trying to help, but I wish they wouldn't treat me as if I am a child._4. We would have won if Jack scored that goal in that match._5. They desired that they had the right to vote._Keys:

24、1. is改为were2. took改为(should)take3. am改为were4. scored前加had5. had改为have一适当形式填空(单句适当形式)1. What do you think would happen if there _(be) no light during the days?2. If he had not made many mistakes, he _ (pass) the test.3. I_ (go) to my cousin's birthday party last night, but I was not available.4.

25、Eye doctors recommend that a child's first eye exam_ (be) at the age of six months old.5. If I_ (know) that it was such a hard job, I_ (ask) Mr. Li for help.6. It is time we_ (take) measures to protect the environment.7. If her lawyer_ (be) here last Sunday, he _ (prevent) her from going.8. If y

26、ou had arrived at the airport ten minutes earlier, you_ (not miss) the flight.9. If you _ (be) here last night, you would have met the well-known cancer expert.10. I would rather he _ (come) tomorrow than today.Keys: 1. were2. would have passed3. would have gone4. (should) be5. had known, would have

27、 asked6. took7. had been, would have prevented8. would not have missed9. had been10. came_一单项选择( )1. The doctor recommended that you_ swim after eating a large meal.A. wouldntB. couldntC. needntD. shouldnt( )2. Seeing the enemy, Gary was behaving as though nothing _.A. happenedB. had happenedC. woul

28、d happenD. was happening( )3. I didnt go to the party, but I do wish I _ there.A. wasB. wereC. had beenD. went( )4. The doctor recommended that I _ here for sunshine to help me to get over my illness.A. would comeB. cameC. had comeD. come( )5. His parents wish was that he _home immediately.A. return

29、edB. would returnC. returnsD. return( )6. - What did Mary say to you?- She suggested that we _go swimming that afternoon.A. mustB. wouldC. shouldD. might( )7. - Did you make it at last?- Yes. But for your help, it_ a serious loss.A. would causeB. must have causedC. would have causedD. may cause( )8.

30、 35 passengers died in the bullet train accident. But for the heroic train driver, many more people_ .A. had diedB. would dieC. would have diedD. died( )9. I still remember it as if it_ yesterday.A. happensB. happenedC. has happenedD. happening( )10. The kind-hearted couple treat the orphan very wel

31、l as if he_ their own son.A. isB. wereC. had beenD. should beKeys: 1. D 2. B 3. C 4. D 5. B6. C 7. C 8. C 9. B10. B二.阅读理解 People from all over the world have different wedding traditions and marriage customs. The one thing that all wedding ceremonies commonly seem to have is the commitment(承诺) of lo

32、ve for all time during a public ceremony. Everyone at a wedding hopes for great happiness between the wedding couple. Wedding traditions are usually a way of showing signs of the hope for great happiness. Some of these traditions are very interesting. In Sweden, the traditional bride will wear three

33、 rings by the end of the wedding ceremony. The first is the engagement(订婚) ring that she entered the ceremony with. The second, the wedding ring, is added to the first. A final ring, however, is added as well. This ring is known as the "motherhood" ring. This is said to show that marriage

34、is about more than just love. It is about building a family. Wedding traditions in the Philippines include the Pandango, a dance which can last for hours. During the Pandango, guests pin (用大头针别住) money to the bride's dress to pay for their honeymoon. A traditional Irish bride may wear a blue wed

35、ding dress-believing blue to be a lucky colour. English Lavender(薰衣草) is often mixed with her wedding flowers. It is traditional for the bride to braid her hair(梳头发)as it is considered a good way to bring luck to the new couple. There are many wedding traditions around the world which may differ fro

36、m what they are used to, but if you are about to plan a wedding, you may find it interesting to include some of these traditions in your own wedding.( )1. What do all wedding ceremonies seem to have in common?A. The commitment of love for all time.B. Happiness between the wedding couple.C. An intere

37、sting life.D. Building a happy family.( )2. In Sweden, the traditional brides third ring shows _ .A. the duties of the new coupleC. the bride will be not only a wB. the great love between the new coupleD. the bride will take care of not only her husband but also his mother( )3. In the Philippines, t

38、he new couple paid for their honeymoon with the money from _.A. the brideB. the bridegroomC. their parentsD. visiting guests( )4. Whats the passage mainly about?A. The reason for different wedding traditions.B. Interesting wedding traditions from different countries.C. The way to prepare for a wedding ceremony.D. Interesting engagement traditions around t