it用法完全归纳

it用法完全归纳
一、it 作人称代词的用法
1. 指事物
作为人称代词，it 可以除人以外的一切事物或动物。

如：
●I dropped my watch and it broke. 我把手表掉在地上摔坏了。

●It’s hard work, but I enjoy it. 工作很辛苦，可是我乐意干。

●“Where is the dog?”“It’s in the bedroom. ”“狗在哪?”“在
卧室里”。

2. 指人
it 指人主要用于指不性别不明的婴儿或用于确认某人的身份。

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. 有人在敲门，一定是邮递员。

【说明】在答语中，常用来指本人，如说It’s me。

3. 代替某些代词
代词it 还可用于代替指示代词this, that 以及复合不定代词something, anything, nothing 等。

如：
●“What’s this?”“It’s a new machine. ”“这是什么?”“是一种新机器”。

●Nothing is wrong, is it? 没出什么问题，是吗?
二、it 作非人称代词的用法
1. 基本用法
it 作非人称代词的用法，主要用
于指时间、距离、价值、天气、气候及温度等自然现象。

如：●现在去那儿已经太迟了。

It’s too late to go there now.
●昨天下了一天的雨。

It rained all day yesterday.
●这里有时会很热。

It can get very hot here.
2. 用于某些句型
It’s time for sth. 该做某事了。

It’s time to do sth. 该做某事的时候了。

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。

(从句谓语用过去式，有时也用“should+动词原形”)
It’s first (second) time + that-从句. 某人第几次干某事。

(从句谓语用现在完成时)
It’s/has been + 时间段+ since-从句. 自从……有一段时间了。

It + be + 时间段+ before-从句. 过多长的时间才……
是该采取措施打击盗版的时
候了。

It’s high time that we took measures to fight privacy.
●这是我第二次来中国。

It’s the second time that I have been in China.
●我们认识三年了。

It’s three years since we got to know each other.
三、it用作形式主语
1. 基本用法
当不定式、动名词、从句等复杂成分用作句子主语时，为保持句
子平衡，通常把真正的主语放在句末，而在句首使用形式主语it。

如：
●记住这一点很重要。

It’s very important to remember this.
●爬山是费劲的事。

It’s hard work climbing mountains.
●他什么时候来还不知道。

It’s unknown when he will come.
2. 用作形式主语的的重要句型
(1) It + be + adj. for (of) sb to do sth 某人做某事……
●他很难下定决心。

It is hard for him to make up his mind.
●她说那样的话，真是太蠢了。

It was foolish of her to say such a thing.
(2) It takes sb + 时间段+ to do sth. 某人做某事花了……时间●要花多年的时间才能掌握一门新的语言。

It takes years to master a new
language.
(3) It is up to sb to do sth. 该由某人做某事
●得由你来作选择。

It’s up to you to make the choice.
(4) It look (seem, appear, happen, occur) that [as if]…似乎……
●他似乎没认出我来。

It seemed as though he didn’t recognize me.
●他打电话时我碰巧不在家。

It happened that I was out when he called.
It appears that…似乎……
It happens that…碰巧……
It occurred to me that…我突然想起……(5) It’s said/reported/known…+ that-从句据说/据报道/大家知道……
(6) If it were not for…/ If it hadn’t been for…若不是因为……Were it not for / Had it not been for…
●要不是他们帮助，这些困难我们不克服不了的。

If it were not for their help/ If it had not been for their help, we couldn’t have got over the difficulties.
(7) It is/was + 被强调部分+ that-从句(强调句型)
●他欣喜地得知失踪的女儿被
找到的消息。

It was with great joy that he received the news that his lost daughter had been found.
直到深夜他才做完实验回家。

It was not until midnight that he went back home after the experiment.
Not until midnight did he go back home after the experiment.
He didn’t go back home after the experiment until midnight.
(8) It is important/natural/necessary/rig ht/strange…+ that-从句(从句谓语用should+动词原形，表示出乎说话人意料或说话人的主观意见)
●很奇怪他竟然这么说。

It was strange that he should say that.
●我们要记住自己的责任，这很必要。

It is necessary that we should remember our responsibilities.
(9) It is a pity/shame…+ that-从句(从句谓语用should+动词原形，表示出乎意料)
●我们竟然输了那场重要的比赛，真可惜。

It’s a pity that we should lose that important match.
(10) It is no good/use + doing sth. 做某事没好处/没用。

●和他争辩没用。

It’s no use arguing with him. Is it any good arguing with him?
四、it用作形式宾语
1. 基本用法
当不定式、动名词、从句等复杂成分用作宾语且其后跟有宾语补足语时，通常会在宾语补足语前使用形式宾语，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)”。

如：
●我发现做好这件事不容易。

I find it difficult to do the job well.
●我认为你最好住这儿。

I think it best that you should stay here.
●我们认为抱怨是没有用的。

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。

如：
●I like it that you came. 你来了，我很高兴。

●I take it (that) he will come on time. 我认为他会准时来的。

●You can put it that it was arranged before. 你可以说这是以前安排的。

●Rumor has it that the defence minister will soon resign. 据传闻，国防部长不久就要辞职。

【说明】能用于此结构的动词不多，常见的有have, take, put, like 等。

(2) 动词+ it + when (if)-从句。

如：
●I dislike it when you whistle.
我不爱听你吹口哨。

●We really appreciate it when she offered to help. 她来帮忙了，我们十分感激。

●I’d prefer it if I didn’t have to do so much work. 要是我不必做那么多工作，那就太好了。

【说明】能用于此结构的动词不多，常见的有enjoy, hate, love, like, dislike, appreciate, prefer 等。

(3) 动词+ prep + it + that-从句。

如：
●See to it that you’re not late again. 注意千万不要再迟到。

●Look to it that this doesn’t happen again. 注意不要再发生这种事。

●You may rely on it that he’ll come to meet you. 你放心，他会来接你的。

●I can’t answer for it that he will come. 我不能保证他会来。

【说明】能用于此结构的动词不多，常见的有see to, look to,
insist on, stick to, depend on, answer for 等。

(4) 动词+ it + 介词短语+ that-从句。

如：
●I owe it to you that I am still alive. 多亏有你我才仍然活着。

●I took it for granted that he would help us. 我认为他会帮助我们的。

【说明】能用于此结构的动词不多，常见的有take it for granted, bring it to sb’s attention, owe it
to sb 等。