It is no wonder that you are breathless.
It is a pity /shame that he should get into the habit of abusing alcohol. （其中，当n.为a pity (a shame /an honor /a Surprise... 等表示出乎意料时，常译为“竟然”， 则 that 从句中的v.用虚拟语气，即should + do） 。 没有这种意义时，则不用虚
③ it + be + n. + to do sth.
“做某事（真）是个…” 常用n.有：good idea / a pity/ a shame等
It is a good idea to quit smoking before one comes pregnant.
It is a pity/shame not to see that scholar in the flesh.
milkman. 3. 代替上文中的指示代词this/that --Who is that over there? --It’s Helen.
“It”用作“非人称代词”
Ⅱ.用作非人称代词
“it”表示天气、时间、日期、距离、价值、度量、温度、 环境，季节，情况等（称为非人称的it）： It is a bit windy. (指天气) It was nearly midnight when she came back（. 指时间 It‘s May 1, 2007. （指日期） It is 150 yuan. （指价格） It is summer now. (指季节)
It is about 5 kilograms. （指度量） It was very quiet in the café. (指环境) It is half an hour’s walk to the city centre (指距离)
How is it going? (指情形)
“It”用作“形式主语” （8）
三、1. It + be + adj. + that从句.
It is very clear that he’s round and tall like a tree.
It is certain that everything will get on well due to our hard work.
3. it + be + V.ed+ that从句.
“据… / 有人（人们）…”
It is reported that many people died in the earthquake.
It is suggested that the students (should) build up their strength.
adj.：legal，illegal，polite，impolite， possible, impossible , clear，obvious， evident , certain，suitable，fit，useful， useless，etc.)
② it + be + adj. + of sb.+ to do sth.
Grammar
The use of “it”
it 真实身份大揭底 Ⅰ.用作人称代词 Ⅱ.用作非人称代词 Ⅲ .It 作形式主语 Ⅳ. It 作形式宾语 Ⅴ. It 用在特定句型中
Ⅵ. It 用在固定习语中
“It”用作“人称代词”
Ⅰபைடு நூலகம்用作人称代词
1. It 指代上文中提到的物、事。（简化语言，避免重复） eg. My pen is missing. I can’t find it.
It is strange that he shouldn’t feel ashamed of his behavior. （当adj.为strange/surprising /natural/ important/necessary等时，that 从句中即 (should ) + do）
2. it + be + n. + that从句.
二、it + be + n./ adj. + doing sth.
t’s no use/useless doing sth 做某事是无用的
t’s no good/a waste of time/fun/worth doing sth
eg . It's no use crying over spilt milk. It's useless thinking too much. It's a waste of time playing computer games.
Xi’an is a beautiful city, isn’t it? Is this your dog？No, it isn’t.
2. 指代性别不明的人（常指baby）/ 说话人不清 楚性别的人（常在打电话、敲门等时）:
eg. The baby cried because it was hungry. There is a knock at the door. It must be the
It's kind of you to help me with the problem.
It’s generous(adj. 慷慨的) of you to donate su a large of money to charity.
（ 此处adj. 通常为描述“人”的形容词： brave, kind，unkind，nice，rude，considerate， careful，careless，silly，foolish，stupid，clever， wise，crazy.）
1. it ：形式主语 2. it ：形式主语 3. it：形式主语
to do ：真正主语（3） doing ：真正主语（1） that从句：真正主语（4）
一、
① it + be + adj. (+ for sb.）+ to do sth
“（对 sb.来说，）做某事是…的。”
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