英语语法：高中英语It的用法.doc

英语语法：高中英语It的用法！ 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: Its 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: Its no good/use doing Its (well)worth doing Its (well)worth ones while doing/to do Its (well)worth while doing/ to do 例: Its 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 Its surprising that (should)竟然 Its a pity/shame that(should)竟然 例: Its important that you should apologize to her for your rudeness.(=Its 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 takesto 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. Its (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. Its (about/high) time that should /v-ed是该做某事的时候了 例: Its(about/high) time that we should take action. 4. Its the x-th time (that) have v-ed第几次做某事了 例: Its 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: Its 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 youll do the task on your own. 2. verb+it+adj./noun (ones) doing (adj.=useless/worth/worthwhile)(noun=no use/no good/worth ones while/a waste of time/money/energy/words) (verb=think, believe,suppose, consider, feel, make, keep) 例: Ill 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: Dont 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, dont 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 cant. 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: Im for it that you will follow their advice.英语语法：高中英语It的用法