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
It's useless thinking too much. It'er games.
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”
Ⅰ.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. Xi’an is a beautiful city, isn’t it? Is this your dog？No, it isn’t.
3. it + be + V.ed+ that从句.
It is reported that many people died in the earthquake. It is suggested that the students (should) build up their strength.
eg. It seems that he will be back in a few days. It happened that he met his teacher in the street.
“It”用作“形式宾语” （ 2）
Ⅳ. It 作“形式宾语” 1. “某些谓v. + it 宾语 + 宾补 （n.\adj.）+ 真宾（to do \doing\that从句）”
“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) （指时间 It was nearly midnight when she came back. It„s May 1, 2017. （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）
常用的v.有: think, believe, make, find, consider, feel,etc. I think it no use arguing with him. I found it very interesting to study English. He made it clear that smoking is banned in the school. He considers it his duty to help those at risk.
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.）
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.
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。”
It is important for us to learn English well
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. The doctor advised Vera strongly that she should take a holiday, but ______ didn’t help. (全国卷III) A. it B. she C. which D. he 4. I’d appreciate ______ if you would like to teach me how to use the computer. (山东) A. that B. it C. this D. you
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 milkman. 3. 代替上文中的指示代词this/that --Who is that over there? --It’s Helen.
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.
“据… / 有人（人们）…”
( 其中，当v.为insist;command, order;suggest, recommend;require, request, demand等时， that 从句中的v.用虚拟语气，即( should ) + do
4. it + Vi+ that从句.
( 常用v.有happen, seem, appear ,looks, 等.)
Exercises Time
I. 单项选择 1. He didn’t make ____ clear when and where the meeting would be held. (天津) A. this B. that C. it D. these 2. ____ is our belief that improvements in health care will lead to a stronger, more prosperous economy. (浙江) A. As B. That C. This D. It
eg . It's no use crying over spilt milk.
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.
2. 某些谓v.+ it 形宾+ 真宾（that/when/if 从句） （常用v. 用：like, love, appreciate;dislike, hate depend on , count on; see to , make sure; take…for granted等。）
eg. I don’t like it when one speaks with his mouthful. eg. You can depend on it that he will come here on time. eg. I would appreciate it if I were admitted to the school football team. eg. I hate it that you speak when your mouth full. eg. Don’t take it for granted that famous brands mean high quality.
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.