it的用法归纳.doc

It” 用法归纳“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(如敲门,打时用)；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…… 请参考课本P157二、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. it替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等       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等       例  It’s kind of you to help me with the problem.2. 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.3. It替代主语从句的常见句型（1）It is + noun +从句       例  It is no secret/surprise that the president wants to have a second term at office.  (2) It is clear ( obvious, true, possible, certain....) that .....该句型中it 是形式主语，真正的主语是that 引导的主语从句，常译为”清楚（显然，真的，肯定．．．）” 是主语从句最常见的一种结构。

It is very clear that he’s round and tall like a tree.= That he’s round and tall like a tree is very clear.（3）It is Vpp that…=sb/sth is to do (verb=say, report, think, believe, hope, expect, agree, accept, determine, intend, plan, understand, know）例  It is said that the couple have got divorced.(=The couple are said to have got divorced.)注意区分: As is said, the couple have got divorced.What is said is that the couple have got divorced.(4). It is  adj.(important, necessary, right, strange, natural, desirable)n. (a pity, a shame, no wonder)                          +that从句用(should+V原)  (表建议suggested, proposed, recommended, advised要求desired, requested, demanded,命令ordered, decided等)该句型和前三个同属一个句型。

由于主句中的形容词,名词,动词不同，且说话人对从句中的事实表示惊讶,那么that 后的从句中要用虚拟语气（should + 动词原形），should意为”竟然,应该”,可以省去但若说话人对从句中的事实不表示惊讶,也可用陈述语气.It is important that we (should) learn English well.It is necessary that he (should) remember these words.It is strange that he didn’t come yesterday.It is a pity that you can’t swim.(5）It verb sb. + clause= It is v-ing + clauseIt+surprise/delight/interest/disappoint/worry/disturb /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.)（6）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)例  It (so) happened/chanced that they were out.(= They happened/chanced to be out.)    It didn’t occur to me that I would be the monitor. 我从没想过我会当班长.   It didn’t occur to her to ask for help. 她从没想过要求助.三、It作主语的常见句型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 (should不可省略)       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.        It was the first time that he had been abroad.5. It be +时间段+since引导的状语从句    主句    从句         意义   is   /         has beenV-ed(瞬间性动词)从过去的一个时间延续至说话的现在自从……有多久了 wasHad v-ed从过去的某个时间点延伸至另一个过去时间点isV-ed(延续性动词)自从动作的结束以来多长时间了不做…已经有多久了例 I t has been three weeks since he arrived here.  他到这儿已经有三周了It is two years since I saw him last time. 自从我上一次见到他已经有两年了It was years since I had seen her.  我和他好几年没见面了。

It’s 10 years that he lived here 他不在这住已经有十年了.6. It is/was/will be(not)+ long/一段时间+ before…过(不)了多长时间某动作就/才发生了       例  It was not long before they arrived. 我们没过多久就到了.       It will be long before my dream comes true. 还要很长时间,我的梦想才会实现.7. It is ... when +时间状语从句,主句中的 it 指时间. 常译为”当．．．的时候，是．．．”It was 5 o’clock when he came here.四、It 作形式宾语it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  (verb=think, believe, suppose, consider, feel, make, find…)       例  I think it hard for you to 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. 。