2021届高考英语通用版一轮复习考点专讲：考点29 原因状语从句 学案 WORD版含解析.doc

1、考点29 原因状语从句 高考频度：原因状语从句是表示原因或理由的，引导这类从句的最常用的连词是because, since, as , now that（既然）等，for 表示因果关系时（它引导的不是从句）为并列连词，语气不如because强。1. because引导的原因状语从句 because表示人们不知道的直接的原因或理由，着重点在从句，其所引导的从句，为全句句意的中心所在。通常用于回答why引出的疑问句，语气最强，除特别强调外，该从句一般位于主句后面。I didnt go abroad with her because I couldnt afford it.我没有和她一起出国是因为费

2、用太高。Dont scamp your work because you are pressed for time.不要因为时间仓促而马马虎虎。I wonder whether his hearing is okay _ he has turned the television up very loud.A. unlessB. althoughC. untilD. because【答案】 D【解析】句意：我想知道他的听力是否还好，因为他把电视的声音开得很大。A. unless除非；B. although虽然；C. until直到；D. because因为。结合句意可知选D。2. as引导的原因

3、状语从句 as引导的原因状语从句所引出的理由在说话人开来已经很明显，或已为听话人所熟悉而不需要强调，从句多位于主句之前，通常可以和since换用，as语气稍弱。As I didnt know the way，I asked a policeman.我不认识路，因而问警察。As it is snowing, we shall not climb the mountain.由于在下雪，我们不去爬山了。1._ you werent there, I left a message.A.AsB.WhenC.ThoughD.For【答案】 A 【解析】句意：因为你不在那儿，所以我给你留言了。此处应用as引

4、导原因状语从句，故选A。when引导时间状语从句；though引导让步状语从句；for用作并列连词表原因时不能位于句首。2. When my father goes somewhere, he always goes along with my mother, _ he doesnt like going alone.A.thoughB.asC.whileD.even if【答案】B 【解析】句意：我爸爸去一些地方时总是和我妈妈一起，因为他不喜欢一个人去。此处用as引导原因状语从句。though尽管；while当时；even if尽管。3. since引导的原因状语从句since表示人们已知的

5、事实，不许强调的原因，故常译为“既然”，通常位于主句前。since从句是次要的，重点强调主句的内容，相当于now that。Since traveling by air is much faster, they decided to take a plane.既然乘飞机旅行快得多，他们就决定坐飞机。Since you wont help me，Ill ask someone else.你既然不帮我，那我就请别人帮忙。Mark needs to learn Chinese _his company is opening a branch in Beijing.A. unless B. until

6、 C. although D. since【答案】D【解析】考查状语从句的连接词。his company is opening a branch in Beijing是学习汉语的原因。unless除非；until直到为止；although尽管；since由于，自从。在句中since是“由于”的意思。句意：马克需要学习汉语，因为他的公司要在北京开分公司。4. now(that)引导的原因状语从句now(that)“因为；既然”，通常可以和since换用。其中that可省去，用来表示一种新的情况，再加以推论。Now(that) youve passed your test you can driv

7、e on your own.你既已考试合格，就可以独自开车了。I do remember，now (that) you mention it.你这一提，我倒的确想起来了。_the term has come to an end, I am going to take a trip for relaxation.A. Now that B. Even ifC.As though D. So that【答案】A【解析】句意：既然这个学期已经结束了，我打算去旅行放松一下。now that既然，引导原因状语从句，符合句意。5. seeing (that)引导的原因状语从句seeing (that)“鉴

8、于；由于”，通常用于非正式文体。Seeing (that) the weather is bad，well stay at home.天气不好，我们还是呆在家里吧。6. in that引导的原因状语从句in that“因为；基于的理由”，可以和because换用，多用于正式文体，它所引导的原因状语从句总是位于主句之后。Advertisement is distinguished from other forms of communication in that the advertiser pays for the message to be delivered. 广告不同于其他交际形式，因为

9、登广告的人要为其所提供的信息付费。Im in a slightly awkward position, in that hes not arriving until 10th.我的处境有点难堪，因为他要十号才来。 The Chinese language _Western languages _, instead of an alphabet, it uses characters which stand for ideas, objects or ideas.A. differs from; in which B. is different from; in thatC. differs f

10、rom; in what D. is different from; in where【答案】B【解析】考查动词短语和连词。表示“与不同”可以用differ from或be different from；in that是固定连词，引导原因状语从句，表示“由于，因为”，故选B项。题组一 能力过关I单项填空1.Perhaps it was_ my father often published his poems in the newspapers that he became known through his literary works.A. beforeB. whenC. ifD. beca

11、use2. _fewer people send letters to one another, the number of people collecting stamps has been steadily in decline.A. BeforeB. AlthoughC.AsD. If3.Why not stay at home _the road is so slippery after the heavy snow?A. since thatB. now thatC. then thatD. after that4._ you have got a job, you should l

12、earn to be independent of your parents.A. SoB. AlthoughC. BeforeD. Now that5.The old man asked Lucy to move to another chair _he wanted to sit next to his wife.A. althoughB. unlessC. becauseD. if6. _ I can never persuade you to give up buying stocks(股票), I can only wish you good luck.A.WhenB.ForC.Si

13、nceD.Although7. The play has remained a mystery _ the producer wants to surprise the audience.A.althoughB.becauseC.unlessD.until8. Mary felt sad over the loss of photos she had shot in Australia, _ that was a memory she especially treasured.A.asB.whichC.whenD.where9. Enjoy the first hour of the day.

14、 This is very important _ it sets the mood for the rest of the day.A.asB.ifC.whenD.where10. I wont attend the party to be held in Marys home, _ I wont stay where I feel Im not welcomed.A.now thatB.so thatC.becauseD.whenII.语法填空阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。Diets have changed in China and so too has

15、 its top crop. Since 2011,the country _1_（grow）more corn than rice. Corn production has jumped nearly 125 percent over _2_ past 25 years, while rice has increased only 7 percent.A taste for meat is _3_ (actual) behind the change: An important part of its corn is used to feed chickens, pigs, and catt

16、le. Another reason for corns rise: The government encourages farmers to grow corn instead of rice _4_ (improve) water quality. Corn uses less water _5_ rice and creates less fertilizer(化肥) runoff. This switch has decreased _6_ (pollute) in the countrys major lakes and reservoirs and made drinking wa

17、ter safer for people.According to the World Bank, China accounts for about 30 percent of total _7_ (globe)fertilizer consumption. The Chinese Ministry of Agriculture finds that between 2005when the government _8_ (start) a soil-testing program _9_ gives specific fertilizer recommendations to farmers

18、 - and 2011, fertilizer use dropped by 7.7 million tons. That prevented the emission(排放) of 51.8 million tons of carbon dioxide. Chinas approach to protecting its environment while _10_ (feed) its citizens offers useful lessons for agriculture and food policymakers worldwide. says the banks Juergen

19、Voegele.题组二体验真题1. (2017新课标卷II改编)The damage is usually more serious on the first plant, but the neighbors, relatively speaking, stay safer _ they heard the alarm and knew what to do.A. though B. unless C. before D. because2.（2016北京卷单项填空）I really enjoy listening to music _ it helps me relax and takes

20、my mind away from other cares of the day.A. becauseB. beforeC. unlessD. until题组一 能力过关单项填空1.D 【解析】分析句子结构可知此处为强调句型，且被强调部分是原因状语从句，故用because引导，其他选项不符合语境。2.C 【解析】考查as引导的原因状语从句。句意：因为越来越少的人互相寄信，因此集邮的人数在持续减少。主句与从句之间有因果关系，因此用as。3.B 【解析】考查原因状语从句连接词。本题两句话之间存在因果关系，故要用表示原因的now that。4.D 【解析】考查状语从句。据语境，你既然有了自己的工作，

21、就应该独立了。now that引导原因状语从句，相当于since。5.C 【解析】句意：那个老人让Lucy去坐另一张椅子，因为他想挨着他妻子坐。后面的从句表示原因，故填because。6. C 【解析】句意：既然我不能说服你放弃买股票，那我只能祝你好运了。since在此引导原因状语从句，意为既然，符合句意。for用作并列连词表示原因时，不能位于句首。7. B 【解析】考查状语从句。句意：这部戏剧仍旧是一个迷，因为创作者想给观众一个惊喜。A. although尽管引导让步状语从句；B. because因为引导原因状语从句；C. unless除非引导条件状语从句；D. until直到引导时间状语从

22、句。故选B。8. A 【解析】考查状语从句。句意：Mary因丢失了她在澳大利亚拍摄的照片而非常伤心，因为那是她格外珍贵的回忆。as意为因为，引导原因状语从句。9. A 【解析】考查状语从句。句意：享受一天中的第一个小时。这很重要，因为这一个小时决定当天其余时间的情绪。as在句中引导原因状语从句。10. C 【解析】考查状语从句。句意：我不会去参加在玛丽家举办的派对，因为我不会待在我觉得自己不受欢迎的地方。根据句意和句子成分可以看出，本空需要从属连词引导原因状语从句，因此选C。II.语法填空【文章大意】本文是一篇说明文。文中讲述了中国为保护环境在农作物种植上做了一些变化并得到了世界上的知名认识的

23、认可。1. has grown 【解析】考查时态。since加时间点，主句要用现在完成时。句意：2011年以来，中国种植的玉米比水稻多。故填has grown。2. the【解析】考查冠词。句意：玉米产量在过去25年里增长了近125%，而大米只增长了7%。故是特指在过去的25年里。故填the。3. actually【解析】考查副词。句意：对肉的需求实际上是这种变化的背后原因。句子结构完整，用副词修饰句子。故填actually。4. to improve 【解析】考查非谓语动词。句意：为了改善水质政府鼓励农民种植玉米而不是大米。没有连词可以且谓语动词是encourages，故improve应该用

24、非谓语动词。此处表示目的，故用不定式。故填to improve。5. than【解析】考查连词。句意：玉米比大米使用的水更少。根据关键词less可知，填比较连词。故填than。6. pollution【解析】考查词性转换。句意：这一转变减少了中国较大的湖泊和水库的污染，使人们的饮用水更加安全。has decreased后跟名词作宾语，故填pollution。7. global【解析】考查词性转换。句意：中国约占全球化肥总消费量的30%。fertilizer consumption是名词短语，故应该用形容词修饰。故填global。8. started【解析】考查谓语动词。句意：在2005年政府开

25、始了一项土壤测试项目。本句是when引导的定语从句，由于时间是2005年，故用过去时。故填started。9. that/which 【解析】考查定语从句关系词。根据空后的谓语动词gives可知，该空缺少主语，指代program并且引导后面的句子。指物用that/which，故填that或者which。10. feeding【解析】考查省略句。句意：中国在养活了中国人民的同时又保护了环境。这一做法为全世界的农业和粮食政策制定人提供了很有用的经验。空格处表示正在进行的动作，while后面省略掉了China is，省略句的原则：在时间状语从句、条件状语从句、，让步状语从句中，如果从句的主语和主句的主语一致且含有be动词时，那么可以把主语和be动词一块省略。故填feeding。题组二体验真题1.D 【解析】句意：对第一株植物的伤害比较严重，但是邻旁的植物相对安全，因为它们听到了警告知道该做什么。根据语境和句意可知，空后是前面的原因，是原因状语从句，故选D。2.A 【解析】考查原因状语从句。句意：我非常喜欢听音乐，因为它能让我放松，使我不去想其他的事情。前后是因果关系，故选A。