“It”作形式主语和形式宾语的用法详解

合集下载

it作形主的用法

it作形主的用法“It作形主的用法”是指使用it做形式主语，即在句子中无实际含义的主语，通常是一些动词、表语或状语从句。

it这个词有多种用法，因此它可以用来代替不同的句子成分。

在英语中，it作形主语最常用于三种情况：1、it作形式主语：在英语中，it常常被用作形式主语，以强调句子的其余部分。

例如：It is said that he is a very good student.It is believed that the earth is round.2、it作形式宾语：it也可以用作形式宾语，用来代替一个真正的宾语，强调句子的其余部分。

例如：She made it clear that she wouldn't go.He proved it wrong that he was not guilty.3、it作形式状语从句：it也可以用作形式状语从句，用来代替一个真正的状语从句，强调句子的其余部分。

例如：He said it as if he had known everything.He did it as though he had done it many times before.此外，it还有一种特殊的用法，即在句中作为虚拟语气的主语。

这种情况下，it用来引出一个虚拟条件句，带有一种意思是“如果……”。

例如：If it rains, we will stay at home.It would be nice if you could come to my party.以上就是“it作形主的用法”的详细说明。

从上文可以看出，it作形式主语、形式宾语和形式状语从句，并在句中作为虚拟语气的主语，是一种常见的用法。

只要我们能够正确地理解它的用法，就能够在日常的学习和交流中正确使用它。

高考语法it用法详解

一. it作人称代词在特定的环境中，it可指人，如指婴儿、性别不详或身份不明的人。

e.g.1. The baby stopped crying as soon as it saw the woman.（指婴儿）2. —Who is it?—It’s me.（性别不详或身份不明）二. it作形式主语或形式宾语it可以作形式主语或形式宾语而把真正的主语或宾语后置。

1. 用it作形式主语的情况：(1) It＋系动词＋形容词＋that从句It is necessary/important/surprising/strange＋that从句，从句中谓语动词常用“should＋动词原形”形式，且should可省略。

(2) It＋系动词＋名词＋that从句It is a pity/a shame/good news/a fact/an honour/a wonder/no wonder/our duty＋that从句。

e.g. It’s no wonder that you’ve achieved so much success.难怪你取得了如此大的成功。

(3) It＋不及物动词＋that从句It seems/happened/turned out /occurs/appears＋that从句。

e.g. It happened that he was out when I called on him.当我去拜访他的时候，碰巧他出去了。

(4) It＋系动词＋过去分词＋that从句It is said /reported/ announced/ believed/ thought/ well known/ hoped/ pointed out/ found out/ suggested/ ordered/ advised/ requested/ insisted/ required/ demanded＋that从句。

it作形式主语或形式宾语的用法

it作形式主语或形式宾语的用法1. it用作形式主语当不定式、动名词、从句等用作主语时，为避免头重脚轻，通常在句首使用形式主语it，而把真正的主语放在句子末尾。

如：It’s a pity to refuse. 拒绝是令人遗憾的。

It’s no use saying any more about it.再谈这事没有用。

It’s not known where she went.她到哪里去了没人知道。

注：It is said / reported / believed / understood that…这类结构中的 it 也是形式主语。

如：It’s reported that two people were injured in the accident. 据报导这次事故中有两人受伤。

2. it用作形式宾语当不定式、动名词、从句等用作宾语且其后跟有宾语补足语时，就应在宾语补足语前使用形式宾语，而将真正的宾语移至句末。

如：I find it easy to get on with her. 我发现她很容易相处。

I think it best that you should stay here. 我认为你最好住这儿。

They haven’t made it known where they are to hold the conference. 他们还没宣布会议在哪里开。

几种特殊的形式宾语it1. enjoy, like, dislike, love, hate, prefer, appreciate等动词后接 if 从句或 when 从句，通常应先在动词后接 it 作形式宾语。

如：She won’t like it if you arrive late. 她不喜欢你迟到。

He hates it when people use his bike. 他讨厌别人用他的自行车。

I hate it if you say such things in public. 我讨厌你在大庭广众之下说那样的事。

it考点讲义：it用作形式主语和形式宾语的用法归纳总结- 高考英语语法二轮复习专题.docx

高中英语语法高考二轮复习it考点讲义【精讲版】it用作形式主语和形式宾语的用法归纳总结一、用作形式主语当不定式、动名词、从句等用作主语时，避免头重脚轻，通常在句首使用形式主语厄而把真正的主语放在句子末尾。

如：It is stupid to do such a thing.做这种事真蠢。

It's no good sitting up too late.熬夜没有好处。

It is necessary that he should be sent there at once.有必要马上派他到那里去。

注：类似以下句子中的il也可视为形式主语：It happened that the harvest was bad in 1988.碰巧1988 年的收成很不好。

It seems that she is afraid to tell them about it.似乎她怕将此事告诉他们。

二、用作形式宾语当不定式、动名词、从句等用作宾语且其后跟有宾语补足语时，就应在宾语补足语前使用形式宾语，而将真正的宾语移至句末。

如：I've made it a rule never to hurry,我已养成凡事从容不迫的习惯。

Do you think it possible to root out crime?你认为可以根除犯罪吗？He found il difficult to breathe at high altitudes.他觉得在高空呼吸困难。

注：通常意义的形式宾语主要见于真正宾语为不定式、动名词、从句等且其后跟有宾语补足语时的情形，即用于“动词+it+宾语补足语+真正的宾语”这样的结构，但以下两类形式宾语却比较特殊，其后没有宾语补足语:1.由于介词后通常不能直接跟that从句作宾语，有个别特殊结构就在介词后先接it作形式宾语，再跟that从句。

如：You may depend on it that it is true.你可以相信这是真的。

it的用法

“It” 用法及其句型和固定搭配，是英语语法的重点、难点，又是近几年考试的热点，因此在复习中应给予足够的重视。

现将it用法归纳如下：一、It用作实词表达以下概念:指代前文提到的事物，前文中的this, that；替代前文中的内容；指代一位性别不明的小孩或未知的人；指代未指明但谈话双方都知道的那件事；指代时间、天气、气候、距离等自然现象。

二、It用作形式主语替代作主语的从句、动词不定式、动名词，而把真正作主语的从句、动词不定式、动名词置于句尾。

It 作形式主语的常见句型：1. 代作主语的动词不定式，其句型为（1）It be adj. (for sb.) to do sth.（2）It be adj. of sb. to do sth.（3）It替代作主语的动名词的常见句型：It’s no good/use doing…It’s (well)worth doing…It’s (well)worth one’s while doing/to do It’s (well)worth while doing/ to do2. It替代作主语的从句常见句型（1）It is + noun +从句（2）.It is adj. +clauseIt’s surprising that… (should)………竟然……It’s a pity/shame that…(should)………竟然…（3）It verb sb. + clause= It is v-ing + clauseIt+surprise/delight/interest/disappoint/worry/disturb/annoy/amaze/bother/concern/frighten/ please/anger sb. that…（4）It verb (to sb.) that…= sb/sth verb to do(verb = appear, seem, come about, emerge, follow, chance, happen, occur, transpire, turn out , work out)（5）It is v-ed that…=sb/sth is to do(verb=say, report, think, believe, hope, expect, agree, accept, decide, determine, intend, plan, understand, know）四、It 作形式宾语用来替代作宾语的从句、动词不定式、动名词，而把真正作宾语的从句、动词不定式、动名词置于句尾。

3.成都专升本语法精讲加练习“It”作形式主语和形式宾语的用法详解

“It”作形式主语和形式宾语“It”作形式主语和形式宾语的用法详解It作形式主语和形式宾语用法，是英语学习的主要语法项目之一。

无论是单项选择，还是完行填空，it用法始终是反复考查的重、热点之一。

现将it在特殊句型中作形式主语和形式宾语用法，进行如下归纳分析，以供学习参考。

一、It 用作形式主语当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用it作形式主语置于句首，而将真正的主语放在句尾。

此时it只起先行引导作用，本身无词义。

e.g. It is wrong to tell a lie. (说谎是错误的。

) 〔It为to tell a lie的形式主语〕It is no use arguing about it. (争吵是没用的。

) 〔It为arguing about it的形式主语〕It is uncertain who will come. (谁要来还不确定。

) 〔It为who will come的形式主语〕It 作形式主语的常见句型：①It + be + 形容词+ to do sth. / doing / that ….e.g. It is very important to learn a foreign language. (学一门外语非常重要。

)It is useless crying over the spilt milk. (覆水难收。

)It was really surprising that she married a man like that.(她嫁给那样的男士真让人惊讶。

)②It + be +名词词组+ doing / that ….e.g. It is no good telling lies. (撒谎没好处。

)It is a pity that you didn’t go to see the film yesterday. (你昨天没看成那部电影真遗憾。

It作形式主语和形式宾语的用法详解

新希望英语语法精讲------“It”作形式主语和形式宾语“It”作形式主语和形式宾语的用法详解It作形式主语和形式宾语用法,是英语学习的主要语法项目之一;无论是单项选择,还是完行填空,it用法始终是反复考查的重、热点之一;现将it在特殊句型中作形式主语和形式宾语用法,进行如下归纳分析,以供学习参考;一、It 用作形式主语当不定式短语、动名词短语或从句在某个句子中作主语时,为保持句子结构前后平衡,避免头重脚轻,因此常用it作形式主语置于句首,而将真正的主语放在句尾;此时it只起先行引导作用,本身无词义;. It is wrong to tell a lie. 说谎是错误的; 〔It为to tell a lie的形式主语〕It is no use arguing about it. 争吵是没用的; 〔It为arguing about it的形式主语〕It is uncertain who will come. 谁要来还不确定; 〔It为who will come的形式主语〕It 作形式主语的常见句型：①It + be + 形容词+ to do sth. / doing / that ….. It is very important to learn a foreign language. 学一门外语非常重要;It is useless crying over the spilt milk. 覆水难收;It was really surprising that she married a man like that.她嫁给那样的男士真让人惊讶;②It + be +名词词组+ doing / that ….. It is no good telling lies. 撒谎没好处;It is a pity that you didn’t go to see the film yesterday. 你昨天没看成那部电影真遗憾;It is a truth that there would be no new China without the Communist Party.没有共产党就没有新中国,这是毋庸质疑的;③It + be + 过去分词+ that ….该句型常见动词有：say, hope, think, suppose, expect, report, know, believe, decide, etc.. It is said that they have invented a new type of computer. 据说他们发明了一种新型电脑;It is believed that China will become one of the strongest countries in the world.大家都相信中国将会步入世界强国之列;It was reported that more than 170 thousand people died in the 2004 tsunami.据报道,至少有十七万人在2004年那场海啸中丧生;④It + seems / appears / happens等不及物动词+ that ….. It seems that he enjoys pop songs very much.似乎他非常喜欢流行歌曲;It appears that Tom might change his mind. 看来汤姆可能会改变主意;⑤若句子是疑问形式,就只能用it作形式主语;. Does it matter much that they won’t come tomorrow他们明天不来很重要吗Is it true that he will go abroad next week 他下周出国是真的吗⑥It + takes + sb. + some time + to do sth. 这是一个表示“某人花多少时间干某事”的句型,其中it是形式主语,代替后面的不定式to do sth.,句型中的sb.也可以省略;. It took me some time to read the reading materials.我花了一些时间才读完那段阅读材料;It took him fourteen hours to go to New Zealand from Shanghai by plane.从上海乘飞机去新西兰花了他14小时;How long does it take you to go to Beijing from Qingdao by train从青岛坐火车到北京一般要花多久时间I am not sure, but I think it takes at least nine hours to get there.我不能肯定,但估计至少要九个钟头才能到那儿;二、It 用作形式宾语当不定式短语、动名词短语或从句在某个句子中作宾语时,为保持句子结构平衡,避免句式结构的混乱,常用it作形式宾语,而将真正的宾语放在句尾;此时it仍只起先行引导作用,本身无词义;下列四种情况须用it 作形式宾语：①当不定式短语、动名词短语或从句在复合宾语结构中作某些动词的宾语时如think, make, find, consider, feel, suppose等；. They found it pleasant that they worked with us Chinese.他们发现与我们中国人一起工作很愉快;I don’t feel it difficult to understand the Special English. 我觉得理解英语特别节目并不难;He makes it a rule never to borrow money. 他立志决不向别人借钱;I think it no need talking about it with them. 我认为没必要跟他们谈;②某些表示“喜、怒、哀、乐”的动词,如like, enjoy, love, hate等,往往不能直接接宾语从句；. I don’t like it that he’s so lazy. 我不喜欢他那么懒惰;I hate it when my mother asks me to eat eggs. 我讨厌母亲要我吃鸡蛋;③that引导的宾语从句不能直接作介词的宾语；. You may depend on it that we shall always help you. 尽管放心,我们会随时帮你的;Would you see to it that she gets home early 你负责保证她早到家,好吗He insisted on it that he was innocent. 他坚持说自己是无辜的;④由及物动词与介词组成的固定搭配中,宾语从句若作该动词的宾语时,须借用it;. I leave it to your own judgement whether you should do it. 我让你自己判断这事是否该做;We owe it to you that there wasn’t a serious accident. 多亏了你才没有发生严重事故;练习一1. Is _______ necessary to complete the design before National DayA. thisB. thatC. itD. he2. I don’t think _______ possible to master a foreign la nguage without much memory work..A. thisB. thatC. itsD. it3. Does _______ matter if he can’t finish the job on time A. this B. that C. he D. it4. Tom’s mother kept telling him that he should work harder, but ____ didn’t help. A. he B. whic h C. she D. it5. _____ is a fact that English is being accepted as an international language. A. There B. This C. That D. It6. I hate _______ when people talk with their mouths full. A. it B. that C. these D. them7. Don’t _______ that all those who get good grades in the entrance examination will prove to be the most successful. A. take as granted B. take this for granted C. take that for granted D. take it for granted8. I like _______ in the autumn when the weather is clear and bright. A. this B. that C. it D. one练习二1. _______ happened _______ he is unfit for the . This; that B. That; that C. It; that D. He; that2. We took _______ for granted that they would accept our . that B. this C. it D. them3. ______ that the scientist will give us a talk next month A. Is true B. Is it true C. It’s true D. It’s truly4. ____ doesn’t matter much _____ dress you are going to . This; that B. That; who C. It; which D. It; who5. _______ is going to America for further study.A. He is said thatB. People said that heC. It was said heD. It is said that he6. They are good friends. _______ is no wonder that they know each other so . This B. That C. There D. It7. Is _______ possible to fly to the moon in a spaceship A. this B. there C. that D. it8. She liked _______ when he kissed her. A. him B. that C. one D. it9. _______ will do you good to do some exercise every morning. A. It B. There C. Those D. One10. We think _______ our duty to pay taxes to our . that B. this C. its D. itKey: 练习一1-8 CDDDDADC 练习二1-5 CCBCD 6-10 DDDADit作形式主语和形式宾语it既可作人称代词,用来表示动物或无生命的物体等,也可以作无人称代词,在句中作主语,表示“时间”、“距离”、“天气”等;它还可以引导强调句,使语气得以加强;此外,it在句中能作引导词,充当句子中的形式上的成分,如形式主语、形式宾语等;㈠it作形式主语：it作形式主语时没有具体的意义,而只是帮助把真正的主语移到句子后部去,使句子显得平稳一些;it作形式主语时,可以代替三种形式：不定式、动名词和主语从句;1. it代替不定式短语常用于下列句型中：It + be +形容词+ for/of sb. to do sth.It + be + 名词+ to do sth.It takes sb. some time to do sth. 干…花了某人…时间It’s up to sb. to do sth. 干…是某人的职责或义务如：①It is everyone’s duty to obey the law.遵守法律是每个人的义务;it作形式主语, 代替不定式短语to obey the law②It is difficult for a foreigner to learn Chinese.对于一个外国人来说,学习汉语是困难的;it作形式主语, 代替不定式短语to learn Chinese③It is not right to use these places as rubbish dumps.把这些地方用来倒垃圾是不对的;it作形式主语, 代替不定式短语to use these places as rubbish dumps④It took them a year to build the bridge.建这座桥花了他们一年的时间;it作形式主语, 代替不定式短语to build the bridge⑤It is bad manners to stare at people.瞪着眼睛看人是不礼貌的;it作形式主语, 代替不定式短语to stare at people⑥It is up to us to help those in need.帮助那些有困难的人是我们的责任;it作形式主语, 代替不定式短语to help those in need⑦It is not up to you to tell me how to do my job.我怎样干我的工作不用你来多嘴;it作形式主语, 代替不定式短语to tell me how to do my job◆ It be + 形容词+ for sb. to do sth.与It be + 形容词+of sb. to do sth.：如果句型中的形容词描述的是sb.的品质、品格,在逻辑上可以作sb.的表语,则sb.前应用介词of,否则就用for;如：①It’s necessary for us to use a short-wave radio to pick up the programmes.我们用一台短波收音机收听这些节目是必要的;②It’s important for us to learn English well.学好英语对我们来说是重要的;③It’s kind of you to help me.感谢你对我的帮助;= You are kind to help me.④It was foolish of him to give up the job.他放弃那工作是愚蠢的= He was foolish to give up the job.⒉ it代替动名词短语：动名词作主语用后置形式的情况远不及不定式那么普遍,常限于no good, no use, useless, waste等词的后面;①It is no good/ use having a car if you can’t drive.如果你不会开车,有车也没用;it作形式主语,代替动名词短语having a car②It is a waste of time watching TV.看电视是浪费时间; it作形式主语,代替动名词短语watching TV③It is no use asking him.问他没有用;it作形式主语,代替动名词短语asking him④It is no use talking to him about it.和他谈这事没有用; it作形式主语,代替动名词短语talking to him about it⒊ it代替主语从句：这个主语从句可以用连词that引导,也可以用连接代词或连接副词引导;如：①It was clear that they had no desire for peace.很清楚他们没有和平的诚意;it作形式主语,代替主语从句that they had no desire for peace②It is doubtful whether she will be able to come.她能否来还很难说;it作形式主语,代替主语从句whether she will be able to come③It was clear enough what she meant.她的意思是够清楚的; it作形式主语,代替主语从句what she meant④It hasn’t been made clear when the new road is to be opened to traffic.还没明确宣布新路什么时候通车; it作形式主语,代替主语从句when the new road is to be opened to traffic⑤It is a mystery to me how it all happened.这都是怎么发生的对于我来说还是一个谜;it作形式主语,代替主语从句how it all happened用it作形式主语,把真正的主语从句移至后面的常见句型有：◆ It is a pity/ a shame/ a fact/ an honour/ good news/ no wonder/ a wonder… that…如：①It was a pity that the engineer couldn’t come.可惜工程师没能够来;②It is a wonder that he continues to gamble when he always loses令人惊讶的是他一直输还一直赌;③It isno wonder that you were late难怪你来晚了;④It is a shame that the rain spoiled our picnic.真可惜,这场雨把我们的野餐给搅了;⑤It is a fact that English is being accepted as international language.英语被认为是国际语言,这是一个事实;◆It is + 形容词如：strange/ natural/ surprising/ obvious/ true/ fortunate/ wonderful/ funny/ possible/ impossible/ likely/ unlikely/ clear/ unusual/ certain/ important…that …如：①It is certain that he will win.他一定会取胜;②It is important that we should learn from each other and help each other.我们应当互相学习,互相帮助,这是很重要的;③It was obvious that the child had been badly treated.很显然那个孩子受过虐待;④It is likely that he will ring me tonight.他今晚可能给我打电话;⑤It is strange that he should have left without telling us. 真奇怪,他也没说一声就走了;⑥It is unlikely that their group will get ahead of us. 他们小组不会赶到我们前头去;◆ It seems/ happened/ turned out/ suddenly struck me/ occurred to me…that …如：①It happened that I wasn’t there that day.恰好那天我不在那里;②It seems that his idea is more practical.看起来他的意见更实际一些;③It suddenly occurred to me that I knew how to solve that problem.我忽然想起我知道怎样解决那个问题;◆It + be + 过去分词如：said/ reported/ announced/ decided/ expected/ hoped/ known/ believed…that…如：①It is hoped that the number of deer will greatly increase very soon.相当于：People hope that the number of deer will greatly increase very soon人们希望鹿的数目将会很快增加;②It is said that nothing has been done about it. 据说至今对此没采取任何措施;③It is reported that more than twenty people were killed in that bus accident.据报道在那次的公共汽车事故中有二十多人丧生;④It is known that he is one of the best teachers in our school.大家都知道他是我们学校最好的教师之一;⑤It is believed that the flood there is the biggest in 100 years.据认为那儿的洪水是百年来最大的洪水;注意要在It is suggested/required/desired/ordered/pr oposed…that…的主语从句中用虚拟语气：should + 动词原形如：①It is requested that he give a performance at the party.有人请求他在聚会上表演一个节目;②It is suggested that we should get everything ready by tonight.建议一切在今晚准备好;③It is ordered that the radio be sent there at once.据命令,这台收音机要立刻送到那里去;◆ It doesn’t matter +连接代词或副词…It doesn’t make too much difference+连接代词或副词…如：①It doesn’t matter whether he comes or not.他来还是不来都没关系;②It won’t make much difference whether you go today or tomorrow.你今天去也好,明天去也好,关系不大;㈡it作形式宾语：it作形式宾语时,可以代替三种形式：不定式、动名词和宾语从句;it作形式宾语时,需具备两个条件：①真正的宾语是不定式、动名词或从句②有宾语补足语具备了这两个条件,形式宾语it一定要用;1. it代替不定式短语think/ find/ feel/ consider/ make/ regard…+ it +形容词/名词+ 不定式短语如：①I find it pleasant to work with him.it 作形式宾语,代替不定式短语to work with him我觉得和他一起工作很愉快;②They felt it difficult to finish the work in such a short time.it 作形式宾语,代替不定式短语to finish the work in such a short time他们认为在这么短的时间内完成这项工作是困难的;③She thinks it her duty to help us. it 作形式宾语,代替不定式短语to help us她觉得帮助我们是她的责任;④I think it my honor to be invited to speak here.it 作形式宾语,代替不定式短语to be invited to speak here我觉得应邀在这儿演讲是我的荣耀;⑤Tom didn’t find it difficult to write letters in Chinese.it 作形式宾语,代替不定式短语to write letters in Chinese汤姆发现用汉语写信不难;⑥All these noises made it impossible for me to go on with the work.it 作形式宾语,代替不定式短语to go on with the work这些噪音使我无法继续工作;⒉ it代替动名词短语这只限于少数句型,在多数情况下用不定式时更多一些如：①The professor considers it no good reading without understanding.这位教授认为阅读而不理解没有益处;②Do you consider it any good trying again你觉得再试会有好处吗③He found it useless no use arguing with him.他发现和他辩论没有用;④He thought it absolutely senseless attempting the impossible.想做不可能的事情,他认为是完全没道理的;⑤I don’t think it worthwhile going to such a place.到这样一个地方去我看是不值得的;⒊it代替宾语从句：如：①We all thought it a pity that the conference should have beencancelled.会议取消了我们都感到很遗憾;②I took it for granted that they were not coming.我想他们准是不会来的了;③I’ll see to it that everything is ready in time.我负责使一切都按时准备好;㈢含it 的常用句型英语中有一些固定句型中含有it,应注意这些句型的使用;1. It be + 被强调部分+ that/ who + 其他成分强调句型可以强调一个句子的主语、宾语、表语及状语等成分;如果被强调的成分是表示人的词,可以用that或whowhom连接其他成分；被强调的成分是表示人以外的词,例如表示事物、时间或地点的词,用that连接其他成分;例如我们可以用强调句型强调下列句子的主语如⑴、宾语如⑵、地点状语如⑶及时间状语如⑷I met Peter in Japan last year.⑴ It was I who/that met Peter in Japan last year.⑵ It was Peter whom/that I met in Japan last year.⑶ It was in Japan that I met Peter last year.⑷ It was last year that I met Peter in Japan.not …until 也可用于强调句型例1Mr Brown didn’t come back until eleven o’clock.可变为：It was not until eleven o’clock that Mr Brown came back.例2 The rain didn’t stop until midnight.可变为：It was not until midnight that the rain stopped.强调句也可变为特殊疑问句例1It was in 1949 that the PRC was founded.可变为：When was it that the PRC was founded 例2 Your dad worked in this factory two years ago.可变为：Where was it that your dad worked two years ago2It’s + 地点状语+ that…强调句It’s +地点名词+ where… 定语从句如：①It is the town where I was born.the town 为地点名词,定语从句这是我出生的镇子;②It was in the town that I was born.in the town为地点状语,强调句型我出生在这个镇子;’s + 时间名词+ when…时间状语从句It’s + 时间状语+that…强调句如：①It was at 8 o’clock that he returned.at 8 o’clock是时间状语,强调句他是在八点钟回来的;②It was 8 o’clock when he returned.8 o’clock 是时间名词,时间状语从句他回来的时候是八点钟;4. if it is convenient to you 如果你方便的话如：If it is convenient to you, you can start tomorrow.如果方便的话,你明天可以动身;5. believe it or not 信不信由你如：①Believe it or not, I’ll go abroad next month.不管你信还是不信,我下个月要出国;②Believer it or not, we were left waiting in the rain for two hours.信不信由你我们冒雨等了两个小时;6. It’s time that…did / should do …定语从句如：①It is time that I went and picked up my daughter from school.我该去学校接我女儿放学了;②It’s high time that we stopped/should stop this practice.我们的确该停止这种做法了;7. It is /has been…since…did…时间状语从句如：It is just a week since we arrived here.我们来这里已一星期了;8.It won’t be …before…用不了多长时间就会…It will be…before…得过多长时间才…It wasn’t …before…没过多长时间就…It was…before…过了多长时间才…①It will be a long time before we finish the task.我们还需要很长时间才能完成这项任务;②It wasn’t long before he learned to use the computer.不久他就学会使用计算机了;③It was some time before he told me about this affair.过了一段时间之后他告诉了我这件事;④It won’t be long before we meet again.不久之后我们还会再见面的;㈣易混用其他句型英语中有一些句型不含it, 但却易被误用了it,常见的有以下句型：⒈ There is something/nothing wrong/ the matter with sb./ sth.如：There is nothing wrong /the matter with him. He’s just pretending.他没什么事,他只是在装呢;2. There is no doubt about…对…毫不怀疑There is no doubt that…对…毫不怀疑如：①There is no doubt about his suitability for the job.毫无疑问,他适合这个工作;②There is no doubt about the fact.关于这个事实毫无怀疑;③There is no doubt that he is hard to deal with.毫无置疑他很难对付;⒊ There is no need for sb. to do sth.没必要…如：①There was no need for him to remain in Paris.他没有必要继续留在巴黎;②There is no need for you to start yet.你现在还不必动身;is no/a possibility that… …没可能/有可能= It is impossible/possible that …如：①There is a possibility that the train may be late.可能火车要晚点;②There is no possibility that we’ll see him this weekend.我们本周末不可能见到他;is a chance t hat …可能…如：There is a chance that the sick child will get well.这个生病的孩子可能会好起来的;be no/ some differences between…and……和…之间没/有区别如：There are some differences between the two languages.这两种语言之间有些区别;7. After what seemed + 时间如：After what seemed a very long time, the wounded soldier came back to life.在经过似乎很长的一段时间之后,那个受伤的士兵苏醒了过来;8. There be difficulty/ trouble in doing sth.干…有困难如：here was no difficulty in finding him.找到他没费什么事;习题演练：is reported that he got seven gold . That B. Word C. It D. Newslong ______ to finish the workA. you will takeB. will you takeC. you will take itD. will it take youno need for us to discuss the problem again. It has already been settled.A. It hasB. There hasC. It isD. There iswas disappointed with the play. I had expected _____ to be much better.A. thatB. thisC. oneD. itdon’t think _______ possible to master a foreign language without much memory work.A. itB. thatC. itsD. this_______ matter if he can’t finish the job on time A. this B. it C. he D. thatyou need my ruler ----No, thanks. I’ve got _______ myself.A. itB. eachC. oneD. the oneperson do you mean----______ who wears a new gold watch.A. The oneB. OneC. EachD. It_____ three years since I left . has been B. was C. had been D. will bewon’t be long _____ the island ________ to our motherland.A. when, returnsB. before, will returnC. since, returnsD. before, returnsmany years is it ______ your family moved hereA. afterB. sinceC. beforeD. untilis a pity that you forgot both her address and her telephone number.A. ItB. ThereC. ThisD. Thatsaw no more than one copy left in the bookshop. Will you go and buy ______A. itB. someC. anyD. oneyou see to ______ that the luggage is brought backA. meB. yourselfC. itD. them_______ that she has lost interest in studying English.A. seemedB. appearsC. looksD. remainshappened that I met one of my friends . I B. That C. It D. Howthink _______ right that you didn’t tell him the bad . it B. its C. you D. that18. _______ to say which one I should choose.A. That’s hardB. It is hardC. There no useD. It no goodsurprised me most was that she had become a famous singer.A. ThatB. ItC. WhatD. Thiswill take you a lot of time to find him in the crowd.A. ItB. IC. WeD. Theyfelt ______ to work for human rights and progress.A. it his dutyB. his dutyC. that is a dutyD. that is his dutyin the west makes ______ a rule to buy Christmas presents for their relatives and friends.A. thatB. itC. thisD. The thingfurther discussion whether we’ll build a library or not.A. WeB. HeC. ItD. The thingis no good _______ without doing anything.A. This, talkingB. It, to talkC. It, talkingD. That, to talkis no difference between . There B. Where C. It D. Whatit _______ that they saw A. she B. that she C. her D. herselfbeing Sunday, the library was . That B. It is C. It D. Thiswas evening _______ we arrived . that B. when C. this D. sincewas in the village ______ now is a small town ________ the earthquake occurred.A. where, whichB. which, whereC. which, thatD. that, wherechildren are as bright as he is, and also, he works very hard.----It’s no ______ that he always gets the first place in any examination.A. questionB. doubtC. problemD. wonder答案与提示：it在此句中是形式主语,真正的主语是that从句;这个句型的结构是：it be +过去分词+that 从句;it takes sb. some time to do sth. 意为“花费时间做某事”;It是形式主语,代替不定式短语;此句是将来时态;本题用的是there be句型;There is no need to…是这个句型的一种表达方式,意思是“没有必要…”;I had expected的宾语是前面所提到的play;英语中,通常用it 和one来替代前面单数名词,可以选C或D, one所代替的是同类事物中“一个”,而it所代替的是前面提到过的同一事物,所以答案为D;to master a foreign language without much memory work是动词不定式短语作think的宾语;当句子的宾语是动词不定式或that从句时,我们通常用it作形式宾语,但是如果宾语不与形容词在一起,一般不能用it作形式宾语;本题是一般疑问句;matter有关系,要紧经常用于否定句和疑问句,常用句型是：Does it matter…It doesn’t matter…;不定代词one常用来代替与前面已提到的一个事物人或东西,以避免重复;one 表示同类事物中的“任一个”,即：表示泛指,而the one则表示确指;人称代词it被用来代替前面提到的那个东西;不定代词each常表示“每一个”的意思;根据题意你要用我的尺子吗不,谢谢;我自己有一支;和结构,应选C;不定代词one 和the one都可以被用来代替前面提到过的一个同类事物人或东西,以避免重复;one表示泛指,而the one表示确指;题意为：“你指的是哪个人”“那位戴一只新金表的;”It is /has been…since…did…时间状语从句意思为：自从…以来已有…时间了;It won’t be …before…“用不了多长时间就会…”,其中before引导的是时间状语从句,所以应用现在时态;It is /has been…since…did…时间状语从句意思为：自从…以来已有…时间了;题意为：你们家搬到这里已多长时间了It is a pity that…其中it是形式主语,that从句是真正的主语;one表示同类事物中的“任一个”,即：表示泛指;人称代词it被用来代替前面提到的那个东西;no more than 表示“仅仅,只有”;it 作形式宾语,真正的宾语是后面的that 从句;it seems/appears that…为固定句型,“似乎…”;选项A的时态不对;it happened that…为固定句型,意思是“碰巧…”;题意为：昨天我碰巧碰到了我一位朋友;it 作形式宾语,真正的宾语是“that you didn’t tell him the bad news”it 作形式主语,后面的不定式短语作真正的主语;what surprised me most 在本题中是主语从句;如果选B, 则应把原题中的was去掉,变为：It surprised me most that she had become a famous singer. it 做形式主语本题用的是句型：It takes sb. some time to do sth. 干…花了某人…时间;其中it作形式主语;feel/ find/ think / consider/ make/ regard…+ it +名词/ 形容词+不定式短语, 其中it做形式宾语,真正的宾语是“to work for human rights and progress”make / find/ think / consider/ feel / regard…+ it +名词/ 形容词+不定式短语, 其中it做形式宾语,真正的宾语是“to buy Christmas presents for their relatives and friends”it作形式主语,真正的主语是后面的从句“whether we’ll build a library or not”本题用的是句型：It is no good doing sth. 意思是“干…没用/好处” 其中it 作形式主语,用来代替后面的动名词短语;本题用的是固定句型：There is no difference between…意思是“和…之间没/有区别”,注意别误选it;本题为一个由强调句变成的一般疑问句,被强调的人称代词为宾格;原句应为：They saw her. 选项B的句子结构语法不对;It being Sunday是独立主格结构,在此相当于原因状语从句;it在此题中表示时间; It’s + 时间名词+ when…；It’s + 时间状语+that… 这是一个强调句;本题中的evening为时间名词,所以应选B;本题第一个空填which, 引导的是一个定语从句,修饰先行词the village; 第二个空是强调句,所以选that,“是在这个村庄发生了地震”;It’s no wonder that…为固定句型,意思是“难怪…”;。

it作形式主语和形式宾语用法

it作形式主语和形式宾语用法2009-09-21 09:58:41| 分类：study | 标签：|字号大中小订阅一、It 用作形式主语当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用it作形式主语置于句首，而将真正的主语放在句尾。

此时it只起先行引导作用 ...一、It 用作形式主语当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用it作形式主语置于句首，而将真正的主语放在句尾。

此时it只起先行引导作用，本身无词义。

e.g. It is wrong to tell a lie.(说谎是错误的。

) 〔It为to tell a lie的形式主语〕It is no use arguing about it.(争吵是没用的。

) 〔It为arguing about it的形式主语〕It is uncertain who will come.(谁要来还不确定。

)It is useless crying over the spilt milk.(覆水难收。

)It was really surprising that she married a man like that.(她嫁给那样的男士真让人惊讶。

)②It + be +名词词组+ doing / that ….e.g. It is no good telling lies.(撒谎没好处。

)It is a pity that you didn’t go to see the film yesterda y.(你昨天没看成那部电影真遗憾。

高中英语课件-it作形式主语及形式宾语句型

like/dislike/love/enjoy/hate/appreciate +it when…
I would appreciate +it +if… 注意：表好恶的动词不能直接接宾语从句，
需要在从句前加上形式宾语it。
ห้องสมุดไป่ตู้
it的固定用法
When it comes to.... 当谈到…；
take it for granted that... 认为…理所当然
It is a fact(a pity, a shame, an honour，no wonder) +that从句注：It is no good (use ) doing sth.(动名词短语做真正主语)
做某事是没益处(没有用的)的
注：区分常见的there be固定句型
There is no doubt that 毫无疑问 There is no need to do 没有必要 There is no point doing sth 做某事无意义
depend on it that...某人相信...
see to it that... 务必，保证
Let it be/go.
顺其自然；
That’s it. Make it. Get it.
对了，正是；成功了；懂了
一. it 用作形式主语 (1) It is+ adj. + that从句/to do sth
① It is clear, obvious,true,possible,certain.... that .....
“....是清楚（显然，真的，肯定）的” ② It is necessary, important, strange, natural.... that .....

It 的用法

It 的用法1：it 做形式主语，不定式to do 或that 引导的句子做真正的主语例句: It is important for us to protect environment. 保护环境对我们来说是很重要的。

（it 做形式主语，真正的主语是to protect environment）即to protect environment is important for us 是本句，但这样显得头重脚轻，所以用it 做形式主语.例句: It is common knowledge that science and technology is the first productive force.( it 做形式主语，that 引导的句子做真正的主语2：it 做形式宾语，不定式to do 或that 做真正的宾语例句：He thinks it very hard to master a foreign language.他认为掌握一门外语是很难的。

（he 做主语，thinks 做谓语，it 做形式宾语，very hard 做宾补，to master a foreign language 做真正的宾语，即He thinks to master a foreign language very hard.例句：He thinks it very essential that he should have a decent job.他认为他应该有一份体面的工作是很必要的即He thinks that he should have a decent job very essential.3: it 用于强调句，其结构是it is \was+强调部分+that例句：It was his carelessness that caused his fatal failure.正是他的粗心导致了他的致命失败。

（强调his carelessness,做caused的主语,即强调主语）例句：It was in the cinema that I came across my former English teacher.在电影院我巧遇我的前任英语老师。

it用法

“It”用法及其句型和固定搭配讲解一、It用作实词表达以下概念:指代前文提到的事物，前文中的this, that；替代前文中的内容；指代一位性别不明的小孩或未知的人；指代未指明但谈话双方都知道的那件事；指代时间、天气、气候、距离等自然现象……二、It用作形式主语It 作形式主语的常见句型：1. 代作主语的动词不定式，其句型为(1) It be adj. (for sb.) to do sth.此处adj. 通常为描述事件的形容词：easy, difficult, hard, necessary, unnecessary, possible, impossible, likely, unlikely, right, wrong, important, unimportant, legal, illegal, well-mannered, ill-mannered, polite, impolite, clear, obvious, certain, suitable, proper, fit, useful, useless, dangerous…例It is illegal (for a teenager) to drive a car without a license.(2) It be adj. of sb. to do sth.此处adj. 通常为描述人的形容词：kind, unkind, nice, rude, cruel, considerate, thoughtful, thoughtless, careful, careless, silly, foolish, stupid, clever, wise, crazy.例It's kind of you to help me with the problem.(3) It替代作主语的动名词的常见句型It's no good/use doing…It's (well)worth doing…It's (well)worth one's while doing/to do…It's (well)worth while doing/ to do例It's no use crying over spilt milk.2. It替代作主语的从句常见句型(1) It is + noun +从句例It is no secret that the president wants to have a second term at office.(2) It is adj./n +clauseIt's surprising that…(should)………竟然……It's a pity/shame that…(should)………竟然……例It's important that you should apologize to her for your rudeness.(=It's of much importance that you should apologize to her for your rudeness.)(3) It verb sb. + clause= It is v-ing + clauseIt+surprise/delight/interest/disappoint/worry/disturb/annoy/amaze/bother/concern/frighten/please/anger sb. that…例It worried me that she drove so fast.(= It was worrying that she drove so fast.)(4) It is done that…=sb/sth is to do(verb=say, report, think, believe, hope, expect, agree, accept, decide, determine, intend, plan, understand, know）例It is said that the couple have gotten divorced.(=The couple are said to have gotten divorced.)(5) It is done that … (should)…(verb=demand, request, require, order, suggest, advise, recommend例It is suggested that they should begin with the third question.三、It作主语的句型1. It takes sb. …to do…(=sb takes…to do…)某人用多长时间做某事例It took the men a week to mend our roof.(= The men took a week to mend our roof.)2. It's (about/high) time that…should /v-ed…是该做某事的时候了例It's(about/high) time that we should take action.3. It's the x-th time (that) …have v-ed…第几次做某事了例It's the third time that he has failed the driving test.4. It is/has been…since …continuous v-ed(延续性动词) 某动作已有多长时间不发生了例It's 10 years that he lived here6. It was(not)…before…过(不)了多长时间某动作发生了例It was not long before they arrived.四、It 作形式宾语It 作形式宾语的常见句型：1. verb+ it+ adj./noun (for/of) to do/clause (verb=think, believe, suppose, consider, feel, make, keep…)例I think it hard for you to do the task on your own./I think it hard that you'll do the task on your own.2. v. +it + prep. + that…owe it to sb. that…把…归功于…leave it to sb that…把…留给某人去做take it for granted that …想当然keep it i n mind that…例Don't bother to arrange anything. Just leave it to me to sort out.3. It用在不能直接跟宾语从句的动词后面，尤其是表示好恶的动词后，enjoy, like, love, dislike, resent, hate, don't mind, be fond of, feel like, see to 宾语从句紧跟it之后例I hate it you can swim so well and I can't.五、强调句型It is/was+被强调部分+ that(who)…强调句型用来强调谓语动词以外的任何句子成分。

“It”用法及其句型和固定搭配讲解

“It”用法及其句型和固定搭配讲解“It”用法及其句型和固定搭配，是高中英语语法的重点、难点，又是近几年高考的热点，因此应给予充分的重视，现将it用法归纳如下:一、It用作实词表达以下概念：指代前文提到的事物，前文中的this，that；替代前文中的内容；指代一位性别不明的小孩或未知的人；指代未指明但谈话双方都知道的那件事；指代时间、天气、气候、距离等自然现象……二、It用作形式主语替代作主语的从句、动词不定式、动名词,而把真正作主语的从句、动词不定式、动名词置于句尾.It 作形式主语的常见句型：1。

代作主语的动词不定式，其句型为（1)It be adj。

（for sb.)to do sth.此处adj。

通常为描述事件的形容词:easy，difficult，hard,necessary，unnecessary，possible，impossible，likely，unlikely，right,wrong，important,unimportant，legal，illegal，well—mannered,ill-mannered,polite，impolite,clear，obvious，certain，suitable，proper，fit，useful,useless，dangerous…例It is illegal（for a teenager)to drive a car without a license.(2）It be adj. of sb。

to do sth.此处adj. 通常为描述人的形容词：kind，unkind，nice，rude，cruel，considerate,thoughtful,thoughtless,careful，careless，silly，foolish,stupid，clever,wise，crazy。

例It’s kind of you to help me with the problem.（3）It替代作主语的动名词的常见句型It’s no good/use doing…It's（well）worth doing…It's（well）worth one’s while doing/to do…It’s（well)worth while doing/ to do例It's no use crying over spilt milk.2。

英语中it的用法

it 在英语中的意思较多，用法较广，现总结如下。

一、it作句子的真正主语1．it 指前面已经提到过的人或事物，有时指心目中的或成为问题的人或事物，作真正主语。

例如：What’s this? －It is a sheep? 这是什么？？这是一只绵羊。

Who is it? －It’s me (I). 谁？？是我。

It’s the wind shaking the window. 是风刮得窗户响。

2．it指时间、季节。

一般用在无人称动词的主语。

例如：What time is it? －It’s nine. 几点了？？九点了。

It’s time for the meeting. Let’s go. 开会的时间到了，我们走吧。

What day is today? －It’s Saturday. 今天星期几？？今天星期六。

What’s the date today? －It is October 1st.今天是几号？？今天是十月一日。

What season is it? －It is summer. 现在是什么季节？？是夏季。

3．it 指气候。

一般作无人称动词的主语。

例如：Is it cold in this room? －No, it isn’t. 屋里冷吗？？不冷。

What’s the weather like today? －It is fine.今天天气怎么样？？是晴天。

It often rains in summer and it often snows in winter in this city.这个城市夏天经常下雨，冬天经常下雪。

4．it指距离、情况等。

一般用作无人称动词的主语。

例如：It is five kilometers from my home to the school.从我家到学校有五公里。

It is very near from this factory to that one.从这个工厂到那个工厂非常近。

形式主语与形式宾语

i t作形式主语和形式宾语的用法it作形式主语和形式宾语的用法It除了用作代词表示指代意义以外，还可以用作形式主语和形式宾语。

这种用法是中学阶段英语学习的主要语法项目之一。

纵观历届中考题，无论是单项选择、完型填空，还是句型转换或翻译，it用法始终是反复考查的重、热点之一。

现将it在特殊句型中作形式主语和形式宾语用法，进行如下归纳分析，以供读者学习和参考。

一、It 用作形式主语1．当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用it作形式主语置于句首，而将真正的主语放在句尾。

此时it只起先行引导作用，本身无词义。

例如：It is wrong to tell a lie. 说谎是错误的。

It is no use arguing about it. 争吵是没用的。

It is uncertain who will come. 谁要来还不确定。

2．It 作形式主语的常见句型① It + be + 形容词+ to do sth. / doing / that ….。

例如：It is very important to learn a foreign language. 学一门外语非常重要。

It is useless crying over the spilt milk. 覆水难收。

It was really surprising that she married a man like that.她嫁给那样的男士真让人惊讶。

② It + be +名词词组+ doing / that ….，例如：It is no good telling lies. 撒谎没好处。

It is a pity that you didn’t go to see the film yesterday. 你昨天没看成那部电影真遗憾。

It is a truth that there would be no new China without the Communist Party.没有共产党就没有新中国，这是毋庸质疑的。

It作形式主语和形式宾语

It作形式主语和形式宾语，虽然是我们高中就学过的语法点，但在考研英语题型中，无论是在阅读还是翻译，常会考查该知识点。

一、it作形式主语。

英语中不定式、动名词、主语从句在作主语时主语往往显得很长，使整个句子看上去有点头重脚轻，这样就借助“it”来作形式上的主语，而把真正的主语移到句子后边去，使全句结构上前后平衡。

“it”并无实际意义。

It之后的谓语部分，可以是be+形容词，be+名词（词组），或be+过去分词等。

1．不定式做真正主语例句1：If you are part of the group which you are addressing, you will be in a position to know the experiences and problems which are common to all of you and it’ll be appropriate for you to make a passing remark about the inedible canteen food or the chairman’s notorious bad taste in ties. (2002 Text1)【结构分析】本句包含由and连接两个并列分句。

第一个分句主干为you will be in a position，不定式to know the experiences and problems 做定语，修饰position，其中which引导定语从句，修饰the experiences and problems。

第二个分句为it’ll be appropriate for you to …，其中it作形式主语，真正的主语为不定式to make a passing remark about…。

【参考译文】如果你是你谈话听众中的一员，你就能够了解你们所共有的经历和问题，而且你也可对餐厅极难吃的食物或者领导在选择领带方面差劲的品味进行评头论足。

it作形式主语和宾语的几种结构

B. 动词+ it + that从句。常见于like, take, have, put等少数动词之后（it相当于that从句的同位语）。
I take it that they will succeed sooner or later.
我认为他们迟早会成功的。
The newspapers have it that some Japanese firms have gone bankrupt.
（他们发现与我们中国人一起工作很愉快。）
I don’t feel it difficult to understand the Special English.
（我觉得理解英语特别节目并不难。）
He makes it a rule never to borrow money.
（他立志决不向别人借钱。）
(我花了一些时间才读完那段阅读材料。)
It took him fourteen hours to go to New Zealand from Shanghai by plane.
(从上海乘飞机去新西兰花了他14小时。)
How long does it take you to go to Beijing from Qingdao by train?
(据说他们发明了一种新型电脑。)
It is believed that China will become one of the strongest countries in the world.
(大家都相信中国将会步入世界强国之列。)
It was reported that more than 170 thousand people died in the 2004 tsunami.

英语中it用法全解析

英语中it用法全解析摘要本文主要介绍了英语中it的用法，包括以下几个方面：it作为人称代词，指代前文提到的或语境中明确的人或物。

it作为非人称代词，表示天气、时间、温度、距离等抽象概念。

it作为形式主语或形式宾语，代替不定式、动名词或从句等真正的主语或宾语。

it用于强调句型，突出句子中的某一成分。

it用于其他常见的句式和短语，表达不同的意思和功能。

1. it作为人称代词it作为人称代词，通常指代前文提到的或语境中明确的人或物。

它在句中可以作主语、宾语、定语或表语等。

例如：句子说明He took a quick look at the house and noticed it was veryold.it指代前文提到的house，作主语。

John hates children, and it is difficult to say why.it指代前面提到的事情，作主语。

She made it clear (that) we were not welcome.it作形式宾语，真正的宾语是that引导的从句。

It's me.it作形式主语，真正的主语是me。

2. it作为非人称代词it作为非人称代词，表示天气、时间、温度、距离等抽象概念。

它在句中通常作主语或宾语。

例如：句子说明It is raining.it表示天气，作主语。

It is an hour's walk from my home to the school.it表示距离，作主语。

It is a pity that I didn't think of it earlier.it表示一般情况，作主语。

I don't like it when you are angry.it指代后面的when引导的从句，作宾语。

3. it作为形式主语或形式宾语当不定式、动名词或从句等用作主语或宾语时，为避免头重脚轻或保持句子平衡，通常在句首使用形式主语或形式宾语it，而把真正的主语或宾语置于句尾。

It的用法及句型总结

It的用法及句型总结"It" 用法及其句型和固定搭配，是高中英语语法的重点、难点，又是近几年高考的热点，因此应给予充分的重视，现将it用法归纳如下：一、It用作实词表达以下概念:指代前文提到的事物，如前文中的this, that；替代前文中的内容；指代一位性别不明的小孩或未知的人；指代未指明但谈话双方都知道的那件事；指代时间、天气、气候、距离等自然现象……二、It用作形式主语替代作主语的从句、动词不定式、动名词，而把真正作主语的从句、动词不定式、动名词置于句尾。

It 作形式主语的常见句型：1. 代作主语的动词不定式，其句型为:(1) It be adj. (for sb.) to do sth.此处adj. 通常为描述事件的形容词：easy, difficult, hard, necessary, unnecessary, possible, impossible, likely, unlikely, right, wrong, important, unimportant, legal, illegal, well-mannered, ill-mannered, polite, impolite, clear, obvious, certain, suitable, proper, fit, useful, useless, dangerous…例: It is illegal (for a teenager) to drive a car without a license.(2) It be adj. of sb. to do sth.此处adj. 通常为描述人的形容词：kind, unkind, nice, rude, cruel, considerate, thoughtful, thoughtless, careful, careless, silly, foolish, stupid, clever, wise, crazy.例: It's kind of you to help me with the problem.(3) It替代作主语的动名词的常见句型:It's no good/use doing…It's (well)worth doing…It's (well)worth on e's while doing/to do…It's (well)worth while doing/ to do例: It's no use crying over spilt milk（覆水难收）.2. It替代作主语的从句常见句型：(1) It is + noun +从句例: It is no secret that the president wants to have a second term at office.(2) It is adj. +clauseIt's surprising that… (should)………竟然……It's a pity/shame that…(should)………竟然……例: It's important that you should apologize to her for your rudeness.(=It's of much importance that you should apologize to her for your rudeness.)(3) It verb sb. + clause= It is v-ing + clauseIt+surprise/delight/interest/disappoint/worry/disturb/annoy/amaze /bother/conc ern/frighten/please/anger sb. that…例: It worried me that she drove so fast.(= It was worrying that she drove so fast.)(4) It verb (to sb.) that…= sb/sth verb to do例: It (so) happened/chanced that they were out.(= They happened/chanced to be out.)(5) It is v-ed that…=sb/sth is to do(verb=say, report, think, believe, hope, expect, agree, accept, decide, determine, intend, plan, understand, know）例: It is said that the couple have gotten divorced.(=The couple are said to have gotten divorced.)(6) It is v-ed that … (should)…(verb=demand, request, require, order, suggest, advise, recommend例 It is suggested that they should begin with the third question.三、It作主语的句型1. It takes sb. … to do…(=sb takes…to do…)某人用多长时间做某事例: It took the men a week to mend our roof.(= The men took a week to mend our roof.)2. It's (just)(un)like sb. to do…（不）像某人做某事的风格例: It was (just) like him to think of helping us.3. It's (about/high) time that… should /v-ed…是该做某事的时候了例: It's(about/high) time that we should take action.4. It's the x-th time (that) … have v-ed…第几次做某事了例: It's the third time that he has failed the driving test.5. It is/has been… since …continuous v-ed(延续性动词) 某动作持续了多长时间例: It's 10 years since he lived here6. It was(not)… before…过(不)了多长时间某动作发生了例: It was not long before they arrived.四、It 作形式宾语用来替代作宾语的从句、动词不定式、动名词，而把真正作宾语的从句、动词不定式、动名词置于句尾。