高二英语语法总结：It用法及其句型和固定搭配讲解　　第二章 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，又是近几年遥的热点，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;指代一位遥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.
　　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 　　(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.
) 　　(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)某人用多遥间做某事 　　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(延续遥动词) 某动作已有多遥间不发生了 　　例 Its 10 years that he lived here 　　6.
It was(not) before过(不)了多遥间某动作发生了 　　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) attendthe 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.
　　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。
　　在遥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 didnt 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 brother.
　　4.
注意强调句型与定语从句的区别 　　例 It was at 7 oclock that he came here yesterday.
( 强调句型) 　　It was 7 oclock 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：遥、做到、说定、赶上、及时到达 　　例 Its 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.
　　2.
as it is 　　(1).
相当于in fact, in reality表示事实上，实际情况是 　　例 We had planed to finish the task today, but as it is we probably wont finish it until next week.
　　(2).
相当于方式状语从句，表示照原样 　　例 Leave the table as it is.
　　3.
as it were 相当于as one might say, that is to say, 表示也就是说，可以说，换句话说 　　例 He is, as it were, a modern Sherlock Holmes.
　　4.
if it werent for/if it hadnt been for用来引导虚拟语气，相当于without, or but for, 表示如果不是，要不是 　　例 If it werent for Tom, I wouldnt be alive today.
　　5.
thats it 　　(1).
相当于Thats all.
Thats so much.
表示至此为止，没有别的了 　　例 You can have one more sweet, and thats it.
　　(2).
相当于 Thats right.
表示对啦 　　例 I guess the key to the problem is thechoice A 　　Thats it.
　　6.
catch it 在口语中，相当于be punished/scolded for doing sth.
wrong.
表示因做错事而挨骂，受责备，受批评，受惩罚 　　例 Well really catch it form our teacher if were late for class again.
　　7.
have it 　　(1).
相当于say, insist表示说，主张，表明，硬说 　　例 Rumour has it that they are getting divorced.
　　(2).
相当于get to know something,表示了解，知道，获悉 　　例 I had it from John that she was going abroad.
　　8.
have what it takes在口语中，相当于be well qualified for, 表示具有遥的条件 　　例 You can take it from me that your daughter has what it takes to be a star.
　　9.
so it seems / appears.
　　10.
Keep at it!
(Dont give up!
)相当于go on,表示继续做，不放弃 　　例 My teacher asked me to keep at it.
　　11.
Go it!
(Go on!
) 拼命干, 莽撞 　　12.
Now you have done it!
(You have done sth.
wrong.
) 　　13.
Now youll catch it!
(Youll be punished.
) 　　14.
As it happened, 在口语中，相当于its a pity that, 表示真不凑巧，真遗憾 　　例 As it happened, they were out.
　　15.
As it turned out,在口语中，相当于it was found to be in the end, 表示较后被证明是 　　例 As it turned out, his statement was false.