C-代词it的基本用法知识梳理代词it一.it用做人称代词的用法it用作代词，意为“它”，既可以指人，也可以指物。
it做人称代词，可以用来代替一个名词、短语、从句或句子，以避免他们在句中的重复。
这是可以指提到过的，也可以指未提到的，在句中做主语、表语和宾语。
1)指事物，it可以指除人以外的任何事物或动物。
I dropped my watch and it broke.我把手表掉在地上摔坏了。
2)指人，it主用用于指性别不明的婴儿或只听其声不见其人的人，如：Is it a boy or a girl?是男孩还是女孩？There is a knock on the door. It must be the postman.“Listen. Someone is crying.” “Oh, it must be Mary.”3）代替某些代词。
代词it可以用于代替指示代词this, that以及复合不定代词something, anyth ing, nothing等，如：“What’s this?” “It’s a new machine.”二.it用作非人称代词的用法1)it用作非人称代词用来指时间、距离、价值、天气、气温及温度等。
如It’s too late to go there now.现在去那已经太迟了。
It rained all day yesterday.昨天下了一整天雨。
2)用于某些句型。
It’s time for sth. 该做某事了。
It’s time to do sth. 是时候该做某事了。
It’s time for sb to do sth. 某人该干某事了。
It’s (about/high) time +that--从句。
某人该做某事了。
It’s first(second)time +that--从句。
某人第几次干某事。
（从句谓语动词用现在完成时）It’s +时间段+since从句。
自从…以来有一段时间了。
It’s +时间段+before 从句。
过多长时间才…三.it用作形式主语的用法。
1)当不定式、动名词、从句等复杂成分做句子主语时，为保持句子的平衡，通常把真正的主语放在句末，而句首使用形式主语it。
如It’s very important to reme mber this.It’s hard work climbing mountains.It’s unknown when he will come.2)it用作形式主语的重要句型：①It+be+adj.+for(of)sb to do sth. 某人做某事是…的It is hard for him to make up his mind.他很难下定决心。
It was foolish of her to say such a thing.她说那样的话，太愚蠢了。
提示：此句型中的介词of和for的区别是：of用于指某人的性格，属性，特征等。
介词for表示对象，意为“对…来说”。
②It takes/took sb+时间段+to do sth.某人做某事花了…时间。
It took me two hours to finish my homework.③It is up to sb to do sth.该由某人做某事了。
It’s up to you to make the choice.该由你来做选择了。
④It looks(seems,appears,happens,occurs) that (as if) …似乎…It seems as though he didn’t recognize me.四.it用作形式宾语的用法。
1)当不定式、动名词、从句等复杂成分用作宾语且后面跟有宾语补足语时，通常会在宾语补足语前使用it作形式宾语，而将真正的宾语移至句末。
其基本结构为“动词+it+宾语补足语+不定式（动名词或从句）”。
I find it difficult to do the job well.I think it best that you stay here.We think it no use complaining.2)用作形式宾语的几个特殊结构：①动词+it+that-从句I think it (that) he will come on time.②动词+it+when(if)-从句We really appreciate it when she offered to help.③动词+prep.+it+that-从句I can’t answer for it that he will come.我不能保证他会来。
④动词+it+介词短语+that-从句I took it for granted that he would help us.五.it在强调句中的用法。
强调句的基本结构是：It+be+被强调部分+that(who)+其他部分。
能力提升单项选择1. It was at the gate ____ he told me the news.A. thatB. whatC. whichD. when2.Is ____necessary to tell his father everythingA. itB. thatC. whatD. he3.Was it in this palace ____ the last emperor died?A. thatB. in whichC. in whereD. which4. Is ____ possible to fly to the moon in a spaceship?A. nowB. manC. thatD. it5.Was it during the Second World War ____he died?A. thatB. whileC. in whichD. then6. Is ____necessary to complete the design before National Day?A. thisB. thatC. itD. he7.I don't think ____possible to master a foreign language without much memory work.A. thisB. thatC. itsD. it8.Does ____matter if he can't finish the job on time?A. thisB. thatC. heD. it9.It was not ____she took off her dark glasses ____ I realized she was a famous film star.A. when; thatB. until; thatC. until; whenD. when; then10. Tom’s mother kept telling him that he should work harder, but ____didn’t help.A. heB. whichC. sheD. it11.____is a fact that English is being accepted as an international language.A. ThereB. ThisC. ThatD. It12. Is ________ possible to fly to the moon in a spaceship?A．now B．man C．that D．it13．Our food and service are better than ________ used to be.A．it B．we C．they D．them14．________ appears to me ________ the report must be true.A．That; it B．It; that C．It; it D．That; that15．He feels ________ duty to help others.A．that he B．that his C．it he D．it his16．Take ________ easy. The roads are icy.([词典] 不紧张; 松懈; 不生气; 不激动)A．it B．them C．us D．you17．________ was ________ who I met in the museum this morning.A．It; him B．It; he C．That; he D. That; him18．—— Have you found the bike you lost yesterday?—— Yes, I've found ________ already.A．it B．that C．the one D．that one19.Someone is at the door, who is ?A. thisB. thatC. itD. he20.—It is raining cats and dogs.— .A. So it isB. So is itC. Neither it isD. Neither is it1. It doesn’t matter…It doesn’t matter what he says. 他说什么都没关系。
2. It appears/ seems/ happens/says that…It seems that he is always correct. 他好像总是对的。
It happened that I had no money with me. 碰巧我当时没有带钱。
3. It is s aid/ reported/ believed/ understood that…It is said that he has joined the Party. 据说他已经入党了。
4. It is a waste of time /money doing sth.It’s a waste of time your talking to him. 你和他谈是浪费时间。
5. (It is) no wonder( that) …It’s no wonder he is not hungry; he has been eating sweets all day.难怪他不饿，他整天在吃糖果。
6. It makes no/mush difference…It’s doesn’t make much difference my being there. 我在不在那儿没有什么影响。