it作形式主语课件ppt.ppt

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1、为避免主语冗长为避免主语冗长, ,句子头重脚轻句子头重脚轻, ,经常经常用用it作形式主语作形式主语, ,主语从句放在后面作主语从句放在后面作真正的主语。真正的主语。1. It is certain that he will succeed.2. It is not known whether he will go there.3. It has not been decided yet when theyll start the project.“It” is used as empty subject.形式主语形式主语1. It is 名词名词 从句从句 It is a fact that

2、 事实是事实是 It is an honor that 非常荣幸非常荣幸 It is common knowledge that 是常识是常识能获邀参加你们的婚礼真是不胜荣幸能获邀参加你们的婚礼真是不胜荣幸风就是流动的空气风就是流动的空气,这是常识这是常识可惜他由于一个拼写错误没有得满分可惜他由于一个拼写错误没有得满分Its a great honor that I have been invited to your wedding.Its common knowledge that wind is moving/flowing air.Its a pity that he didnt get

3、 full marks because of a spelling mistake.句型句型1. 2. It is + adj. +从句从句 Its certain that 肯定肯定 It is possible that. 很可能很可能 It is unlikely that. 不可能不可能 It is obvious that 很明显很明显 It is necessary important natural. that*_(很可能很可能)she will come back tomorrow.*_(很明显很明显)this measure is effective.+(should) +d

4、oIt is possible thatIt is obvious that句型句型2. 另注意在主语从句中用来表示另注意在主语从句中用来表示惊奇、惊奇、不相信、惋惜、理应如此不相信、惋惜、理应如此等语气时，等语气时，谓语动词要用谓语动词要用 虚拟语气虚拟语气 “(should) +do”，常用的句型有：，常用的句型有： It is necessary (important, natural, strange, etc.) that It is suggested (requested, proposed, desired, etc.) that 3. It happens (seems, l

5、ooks, appears ) 3. It happens (seems, looks, appears ) that.that.该句型中该句型中it是形式主语，是形式主语，that 引导的是主语引导的是主语从句从句,主句中的主句中的happen, seem 等词是不及物动词等词是不及物动词 It happened ( so happened ) that he met his It happened ( so happened ) that he met his teacher in the street. teacher in the street. 碰巧碰巧It seems that h

6、e will be back in a few days. It seems that he will be back in a few days. 句型句型3. It seems that sb. do/ be doing/ have done/ had done= Sb. seems to do/ be doing/ have done/to be done/to have beenIt seemed that he had been to Beijing before .=He seemed to have been to Beijing before. It +不及物动词不及物动词+从

7、句从句 It happened that. 碰巧碰巧 It occurred to me that我突然想起我突然想起*_(刚好刚好)I came into the office at that time.*_(我突然想起我突然想起)I forget to sent the letter.It happened thatIt occurred to me that句型句型4. 据说他读过这篇小说据说他读过这篇小说 . Itwassaidthat he had read this novel.=He was said tohave read this novel. It + be + -ed 分

8、词分词+ that-从句从句It is said that 据说It is known that 据了解It is reported that据报道It is believed that据认为 1.据说她两年前在美国留学据说她两年前在美国留学 Its said that he studied in America two years ago2. 据说她现在正在美国留学据说她现在正在美国留学 Its said that he is now studying in America 3.据说她现在懂三国外语据说她现在懂三国外语 Its said that he knows three foreign

9、 languagesHe is said to have studied in America two years ago.He is said to be studying in America now.He is said to know three foreign languages.It is suggested ( ordered, required . ) It is suggested ( ordered, required . ) that .that .该句型和上一个同属一个句型。主句中的该句型和上一个同属一个句型。主句中的过去分词是表示请求，建议，命令等词时，过去分词是表示

10、请求，建议，命令等词时，that 后的从句要用虚拟语气（后的从句要用虚拟语气（should + 动词原形），动词原形），should 可以省。常译为可以省。常译为“ 据建议；有命据建议；有命令令）”。 It is suggested that the meeting ( should ) be put It is suggested that the meeting ( should ) be put off. off. It was ordered that we ( should ) arrive there in It was ordered that we ( should ) arr

11、ive there in two hours.two hours. 注意注意It is doubtful whether she will be able to come她是否能来还不还说。她是否能来还不还说。It was clear enough what she meant.她的意思还不太清楚。她的意思还不太清楚。It wont make too much difference whether he will join us.他是否参加我们队不会太重要。他是否参加我们队不会太重要。Has it been found out who set the record? 是谁破了纪录弄清楚了吗？是

12、谁破了纪录弄清楚了吗？5、可用、可用whether和疑问词引导从句的有：和疑问词引导从句的有： It is doubtful (not known, not decided, not made clear, to be found out, being considered, a mystery, a question, + that/whether句型句型5It is still a question when we shall have our sports meeting. It is a mystery to me how it all happened.这事是怎么发生的还是个谜。这事

13、是怎么发生的还是个谜。It hasnt made clear when the new road is to be opened to traffic.新路什么时候通车还不清楚。新路什么时候通车还不清楚。It doesnt matter how/ whether 结构结构中的主语从句不可提前。中的主语从句不可提前。 该句型中该句型中whether (if) 引引导的从句是真正主语，该句型常译导的从句是真正主语，该句型常译为为“不论（是否）不论（是否） 没关系没关系。It doesnt matter if they are old. It doesnt matter if they are ol

14、d. It doesnt matter who will go instead of me.谁代替我去不重要。谁代替我去不重要。句型句型6It doesnt matter whether he is wrong or not. (right)Whether he is wrong or not doesnt matter. (wrong)该句型是强调句型。被强调部分可以是主语，该句型是强调句型。被强调部分可以是主语，宾语，表语或状语。强调的主语如果是人，宾语，表语或状语。强调的主语如果是人，that 可以由可以由 who 换用。换用。It was It was about 600 years

15、agoabout 600 years ago that the first that the first clock was made. clock was made. It was It was they they that (who ) cleaned the that (who ) cleaned the classroom yesterday. classroom yesterday. It was It was in the streetin the street that I met her father that I met her father. . 7. It is + 被强

16、调部分被强调部分 + that .1.正确选用正确选用is 或或was.2. 强调部分是人，可以用强调部分是人，可以用who.3. 强调主语，强调主语，that 或或who 后面的后面的谓语形式与主语一致谓语形式与主语一致不能强调谓语不能强调谓语 注意注意8. It is not until + 8. It is not until + 被强调部分被强调部分 + that .+ that . 该句型也是强调句型。主要用于强凋时该句型也是强调句型。主要用于强凋时间状语，译成汉语间状语，译成汉语 “直到直到才才”，可，可以说是以说是 not . until . 的强调形式。的强调形式。=It wa

17、s not until she took off her dark glasses that =It was not until she took off her dark glasses that I realized she was a famous film star.I realized she was a famous film star.I didnt realize she was a famous film star until she I didnt realize she was a famous film star until she took off her dark

18、glasses.took off her dark glasses. = Not until she took off her dark glasses did I = Not until she took off her dark glasses did I realize she was a famous film star.realize she was a famous film star.9. It is the first ( second ) time that 9. It is the first ( second ) time that 该句型要和上一个句型区别开来。该句型中

19、的该句型要和上一个句型区别开来。该句型中的 that 从句不用虚拟语气，而用完成时态。至于用从句不用虚拟语气，而用完成时态。至于用什么完成时态，由主句的谓语动词的时态决定。什么完成时态，由主句的谓语动词的时态决定。如果是一般现在时，后面从句用现在完成时态；如果是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用过去完成时态。如果是一般过去时，后面从句则用过去完成时态。该结构中该结构中 that 可以省去；可以省去；it 有时用有时用 this 替换，替换，常译为常译为“是第一（二）是第一（二）次次”。 It (This) is the first time I have bee

20、n here. It (This) is the first time I have been here. It ( This) was the first time I had been here.It ( This) was the first time I had been here.10. It is since .10. It is since . 该句型主要用作处理瞬间动词的完成时，又要该句型主要用作处理瞬间动词的完成时，又要和表示一段时间的时间状语连用的问题。主句中和表示一段时间的时间状语连用的问题。主句中是时间作表语，其时态是现在时或完成时，是时间作表语，其时态是现在时或完成时

21、，since 引导的从句通常是一般过去时态，而且是瞬间动引导的从句通常是一般过去时态，而且是瞬间动词。如果主句是一般过去时，从句则用过去完成词。如果主句是一般过去时，从句则用过去完成时。时。 It is ( has been ) 5 years since his father died. It was 1949 when I was born.It was in 1949 that I was born.区别句下面这个句子：区别句下面这个句子：11. It is . when .11. It is . when . 该句型中的该句型中的 when 引导的是一个时间状语引导的是一个时间状语从句

22、，主句中的从句，主句中的 it 指时间，表语由具体的时指时间，表语由具体的时间充当。常译为间充当。常译为“当当的时候，是的时候，是”。 It was 5 oclock when he came here.It was 5 oclock when he came here. 强调句型强调句型时间状语从句时间状语从句12. It be . before .12. It be . before .该句型主句中的该句型主句中的 it 指时间指时间, 主句中的时态常主句中的时态常是一般是一般将来将来时或过去时两种时态主句中的时或过去时两种时态主句中的表语多是表语多是long, not long , 3

23、days , 2 weeks 等表示时间段的词或短语。常译为等表示时间段的词或短语。常译为“之之后后”。 It was 3 days before he went to Beijing. It was 3 days before he went to Beijing. It will be not long before he finishes his It will be not long before he finishes his job. job. 要过好几个月她才会适应这项工作要过好几个月她才会适应这项工作It will be months before she is fit for

24、 the job.It will be months before she is fit for the job.过了一星期他回来了过了一星期他回来了It was a week before he came backIt was a week before he came back.过了不久，她认识到她错了过了不久，她认识到她错了It was not long before she realized she was wrong.It was not long before she realized she was wrong.他离开中国已经他离开中国已经10年了年了It is 10 years

25、 since he left China.It is 10 years since he left China.如以过去某一时间为基点，则为：如以过去某一时间为基点，则为：It was 10 years since He had left China.区别句意区别句意：It is three years since I It is three years since I livedlived here. here.It is three years since I It is three years since I have livedhave lived here. here.It is t

26、hree years since I It is three years since I began to livebegan to live here here. .我不住在这里已经有三年了。后两句的含义是：我住在这里已经有三年了。后两句的含义是：我住在这里已经有三年了。It is + 段时间段时间 + since. / It has been + 段时间段时间 + since.表示表示“从从起已有多长时间起已有多长时间了了” 。It is three years since he smoked. 他不吸烟已有他不吸烟已有 3 年了。年了。 试比较：试比较：It is three years

27、 since he began to smoke. It is three years since he has smoked. 两句均意为：他吸烟已有两句均意为：他吸烟已有 3 年了。年了。用法：用法：since 从句中常用一般过去时，从句中常用一般过去时，(1)若从句中是持续若从句中是持续性动词的一般过去时，性动词的一般过去时， 则表示该动作结束有多长时间则表示该动作结束有多长时间 了了则翻译为则翻译为“已经不再已经不再多长时间了多长时间了”； ，(2)若是短暂性若是短暂性动词，的一般过去时，则表示该动作发生后，距离现在有动词，的一般过去时，则表示该动作发生后，距离现在有多长时间了则翻译为

28、多长时间了则翻译为“已经已经.多长时间了多长时间了” (3)若是持续若是持续性动词的现在完成时，性动词的现在完成时， 则表示动作和状态延续到现在则表示动作和状态延续到现在 (说说话时刻话时刻)， 其表示的时间的起点应从动作发生之时算起。其表示的时间的起点应从动作发生之时算起。 注意：在这种结构中，注意：在这种结构中， since 引导的从句绝对不能引导的从句绝对不能用否定式的谓语动词来表示否定意义。用否定式的谓语动词来表示否定意义。 他好久没学汉语了。 误：It is a long time since he didnt study Chinese. 正：Its a long time sin

29、ce he studied Chinese. (studied 为持续性动词， 应从其动作结束时算起) It is three years since I was a college student.我已经毕业三年了。我已经毕业三年了。It is three years since I became/have been a college student.我成为一名大学生已经两年了我成为一名大学生已经两年了13. It takes sb. to do sth.13. It takes sb. to do sth.该句型中的不定式是真正的主语，该句型中的不定式是真正的主语，it是是形式主语，句型

30、中的直接宾语是时间。形式主语，句型中的直接宾语是时间。常译为常译为“做做要花费某人要花费某人”。 It took thousands of people many years It took thousands of people many years to build the Great Wall.to build the Great Wall. 14. It is no good (use ) doing sth.14. It is no good (use ) doing sth.该句型中的真正主语是动名词短语，主该句型中的真正主语是动名词短语，主句中的表语可以是句中的表语可以是no g

31、ood , ( not any good ) , no use , ( not any use )。 It is no good learning English without It is no good learning English without speaking English.speaking English. It is no use for him to learn English It is no use for him to learn English without speaking it.without speaking it.15. It looks ( seems

32、 ) as if .15. It looks ( seems ) as if . 该句型中该句型中it 无意义。无意义。 as if 引导一个状引导一个状语从句。常译为，语从句。常译为，“看起来好象看起来好象 如果与事实不相符合，则用虚拟语气如果与事实不相符合，则用虚拟语气 It looks as if he is ill.It looks as if he is ill.（真的病了）（真的病了） It looks as if he were ill. It looks as if he were ill. （没有生病）（没有生病） It seemed as if he were dying.

33、 It seemed as if he were dying. 该句型中的不定式短语是真正主语，如果不定式该句型中的不定式短语是真正主语，如果不定式的逻辑主语是由的逻辑主语是由 of 引起，主句中的形容词必须是引起，主句中的形容词必须是能表示逻辑主语特征的形容词。常见的有能表示逻辑主语特征的形容词。常见的有: bad, brave, careless, clever, cruel, foolish, good (好心的好心的), honest, horrible, kind, lazy, modest, naughty, nice (有教养的有教养的), polite, rude, silly

34、, stupid, wise, wrong (错误的错误的)等。等。 这个句型可以改写为：这个句型可以改写为：sb. is kind to do sth. It is kind of you to say so. It is kind of you to say so. You are kind to say so. You are kind to say so. 17. It is necessary ( for sb. ) to do sth.17. It is necessary ( for sb. ) to do sth. 该句型与上一个同属一个句型。如果不定式的逻辑主语该句型与上一个

35、同属一个句型。如果不定式的逻辑主语是由是由for 引起，主句中的形容词通常是表示重要性，紧迫引起，主句中的形容词通常是表示重要性，紧迫性性,频繁程度频繁程度,难易难易,安全等情况的形容词。常见的形容词有：安全等情况的形容词。常见的形容词有：在在中的形容词作表语可以用从句改写，如：中的形容词作表语可以用从句改写，如： It is important for her to come to the party. It is important for her to come to the party. It is important that she (should ) come to the It

36、 is important that she (should ) come to the party party （1）if 引导的主语从句不可居于复合句句首。引导的主语从句不可居于复合句句首。（2）It is said /reported结构中的主语从句不可提前。结构中的主语从句不可提前。例如：例如： It is said that President Jiang will visit our school next week. That President Jiang will visit our school next week is said. （3）It happens/occurs

37、结构中的主语从句不可提前。例结构中的主语从句不可提前。例如：如： It occurred to him that he failed in the examination. That he failed in the examination occurred to him. (5) 含主语从句的复合句是疑问句时，含主语从句的复合句是疑问句时，主语从句不可提前。例如：主语从句不可提前。例如：Is it likely that it will rain in the evening? (right)Is that it will rain in the evening likely? (wrong

38、)（4）It doesnt matter how/whether 结构中的结构中的主语从句不可提前。例如：主语从句不可提前。例如： It doesnt matter whether he is wrong or not. Whether he is wrong or not doesnt matter. 1.It now appears _ they are in need of help. A. that B. which C. what D. how2.It is good news _ they will arrive in a few days. A. which B. what C.

39、 that D. how3.It _ Joe drives badly. A. thought that B. thinks that C. is thought D. is thought that4.I have always been honest and straightforward, and it doesnt matter _that Im talking to.A. who is it B. who it is C. it is who D. it is whom 5. It is pretty well understood _ controls the flow of ca

40、rbon dioxide in and out the atmosphere today. A. that B. when C. what D. how 选C，从句缺少主语，what正好可以作为主语，意思大家知道是什么控制着二氧化碳进出大气层。 6.It is important that _ our education in all available ways. A. we must develop B. we shall develop C. we would develop D. we should develop7.It is necessary that _ by the end

41、of the week. A. we got everything ready B. we have got everything ready C. We get everything ready D. we must get everything ready 8.It was natural that _. A. my pictures would surprise them B. my pictures surprised them C. my pictures should surprise them D. my pictures would have surprised them9.I

42、 wonder _. A. whether or not Ill catch the last bus B. if or not Ill catch the last bus C. that Ill catch the last bus or not D. that Ill catch the last bus10. _ made the school proud was_ more than 90 of the students had been admitted to key universities. A. What; because B. What ; thatC. That ; wh

43、at D. That ; because意思：令这所学校骄傲的是意思：令这所学校骄傲的是90的学生都被的学生都被重点大学录取了重点大学录取了 B 是个主语从句是个主语从句 和表语从句和表语从句11. _ we will go camping tomorrow depends on the weather. A. If B. Whether C. That D. Where12. _ that they can pass the written exam this time. A. That is hoped B. It is hoped C. It hopes D. That hopes 13

44、. _ leaves the room last ought to turn off the lights. A. Anyone B. The person C. Whoever D. Who 14. _ is a fact that English is being accepted as an international language. A. There B. This C. That D. ItCD 15. _ in the newspaper that the price of food will go up. A. It says B. It is said C. It has

45、said D. He is said16. It worried her a bit _her hair was turning grey. A. while B. that C. if D. forBB 17. The Foreign Minister said, “_ our hope that the two sides will work towards peace.” A. This is B. There is C. That is D. It is D 18. It is necessary that a college student _ at least a foreign

46、language. A. masters B. should master C. mastered D. will masterB19. _ his dream of going to college will come true is uncertain.A.That B. Whether C. If D. Even if20. It is known to us _ where there is pollution, there is harm.A. which B. where C. what D. that21. - I saw your neighbor break your win

47、dow with a basketball. - _ it made me nearly mad. A. That he broke B. What he broke C. He broke D. His break22.It remains a question _ we can get so much money in such a short time. A.how B. that C. when D. what汉译英汉译英1.很遗憾我们输了这场比赛。很遗憾我们输了这场比赛。2 他在考试中作弊是事实。他在考试中作弊是事实。3 这幅画好像挂倒了这幅画好像挂倒了 (appear)4 车祸发生

48、的时候碰巧我在我的一个朋友散步车祸发生的时候碰巧我在我的一个朋友散步 (happen)5 今年这所大学将招收更多的新生是真的今年这所大学将招收更多的新生是真的 6 知识就是力量知识就是力量,这一点是不言而喻的这一点是不言而喻的clear7一般认为一般认为,印第安人是美洲大陆最早的居民印第安人是美洲大陆最早的居民8学会处理各种挑战对我们来说是很有必要的学会处理各种挑战对我们来说是很有必要的homework这样就构成了下面一些常用句型这样就构成了下面一些常用句型: 1) It is + n. +从句从句 It is a pity/shame that. 遗憾的是遗憾的是 It is a surpr

49、ise that令人惊奇的是令人惊奇的是 It is a fact that 是事实是事实 It is common knowledge that 是常识是常识*1_(很遗憾很遗憾)we lost the match.2 _(这是事实这是事实)he cheated in the exam.It is a pity thatIt is a fact that3 这幅画好像倒挂了这幅画好像倒挂了 (appear)4车祸发生的时候碰巧我在我的一个朋友散步车祸发生的时候碰巧我在我的一个朋友散步 (happen)It appears that this picture hangs upside down

50、It happened that I was walking with one of my friends when the car accident occurredI happened to be walking with one of my friends when the car accident occurred5 今年这所大学将招收更多的新生是真的今年这所大学将招收更多的新生是真的 6 知识就是力量知识就是力量,这一点是不言而喻的这一点是不言而喻的8学会处理生活中的各种挑战对我们来说是很有必要的学会处理生活中的各种挑战对我们来说是很有必要的Its true that the uni