It的用法及句型总结
\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 one'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. +clause
It'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 + clause
It+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 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 here
6. 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。
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. verb+it+adj./noun (one's) doing (adj.=useless/worth/worthwhile)(noun=no use/no good/worth one's while/a waste of time/money/energy/words) (verb=think, believe,suppose, consider, feel, make, keep?)
例: I'll make it worth your while telling me about his secret.
3. verb+it+ important/unimportant/necessary/unnecessary/natural/essential that ? (should)?
verb+it+of much/great/no/little importance that?(should)? (verb=think, believe, suppose, consider, feel, make, keep?)
例: I think it important that you (should) attend the conference. 4. verb + it+ as+ noun/adj.+ clause (verb=accept, regard, take, see, view) 例: The lecturer takes it as encouraging when so many students attend his lecture. 5. 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 in mind that?
例: Don't bother to arrange anything. Just leave it to me to sort out. 6. 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.
7. It用在不能直接跟宾语从句的介词后面，宾语从句紧跟it之后（except that例外） 例: I'm for it that you will follow their advice. 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。当被强调部分是人时也可以用who。 在使用强调句型时需注意以下几点： 1. 请注意强调句型的特殊疑问句
例: When was it that he changed his mind to take part in the activity？ 2. 在强调原因状语从句时，只能强调由because所引导的从句
例: It was because he was ill that he didn't come to school yesterday. 3. 在强调not ? until结构时必须把not与until一起放到被强调的位置上
例: It was not until she took off her dark glasses that I realized she was my sister. 4. 注意强调句型与定语从句的区别
例: It was at 7 o'clock that he came here yesterday.( 强调句型) It was 7 o'clock when he came here yesterday.(定语从句) 六、It 常用的固定搭配 1. make it
(1)在口语当中相当于succeed,表示：成功、做到、说定、赶上、及时到达 例: It's hard to make it to the top in show business. (2)在口语中相当于fix the date for,表示“约定好时间” 例: —Shall we meet next week? —OK. We just make it next Saturday.