文档介绍：It的用法
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”。
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。
1. It is Friday today.
2. It was very cold last Monday.
3. It is about 8:30 now.
4. It is about 25km from Linquan to Fuyang.
5. It lies in the south of Anhui.
6. It is 40°C ! You got a high fever!
date
weather
time
distance
place
temperature
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 + 时间段 + since. 自从……有一段时间了。
It’s + 时间段 + before. 过多长的时间才… it’s=it was
It‘s + 时间段 + that. …多久了
It's + 时间段 + when ...是在某个时刻
It is time for breakfast.
It is time to have breakfast.
It is time for us to have breakfast.
It is the first time I’ve been here.
It is two weeks since I saw him
It's ten years before I graduated.
It's ten years that I've lived here for
It was ten years ago when I graduated
2) It is V-ed + that
① It is said (reported, learned) + that…
It is said that he has come to Beijing.
② It is suggested ( ordered, demanded, insisted, commanded) + that …
从句中的过去分词是表示请求，建议，命令等词时， that后的从句要用虚拟语气(should + V原形). Should可以省略。译为“据建议；有命令…”
It is suggested that the meeting (should) be put off.
3) It is a pity (a shame) that…
That 后的从句一般用虚拟语气 (should+V原形), should 可以省略. 表示出乎意料，译为 ”竟然“。没有这种意义时，则不用虚拟语气。
It is a pity that such a thing (should) happen in your class.
(4) It takes sb. + 时间段 + to do sth. 某人做某事花了……时间
It takes years to master a new language. 要花多年的时间才能掌握一门新的语言。
【Tip】此句型可以有以下多变种变体：
It took me an hour