连接代词：who whoever whom whose what whatever which whichever
连接副词：when where how why
1. It 作形式主语和it引导强调句的比较
It is still a question whether she will come or not.
It is strange that you should like him.
It is still unknown which team will win the match.
It turned out that……;
It has been proved that……;
It happened/occurred that……;
It is well-known that……等等
强调主语：It is the times that produce their heroes.时势造英雄
强调宾语：It is English that Prof.Lin teaches us.
强调状语：It was in shanghai that I saw the film.
2. 用it 作形式主语的结构
(1) It is +名词+that从句
It is a fact that … 事实是……
It is an honor that …非常荣幸
It is common knowledge that …是常识
(2) it is +形容词+that从句
It is natural that… 很自然……
It is strange that… 奇怪的是……
(3) it +不及物动词+that从句
It seems that… 似乎……
It happened that… 碰巧……
(4) it is+过去分词+that从句
It is reported that… 据报道……
It has been proved that… 已证实……
(2) It is said , (reported) …结构中的主语从句不可提前。例如：
It is said that President Jingo will visit our school next week.
(3) It happens…, It occurs… 结构中的主语从句不可提前。例如：
It occurred to him that he failed in the examination.
(4) It doesn’t matter how/whether …结构中的主语从句不可提前。例如：
It doesn’t matter whether he is wrong or not..
Is it likely that it will rain in the evening?
4. What 与that 在引导主语从句时的区别
What 引导主语从句时在从句中充当句子成分，如主语.宾语.表语，而that 则不然。例如：
What you said yesterday is right.
1、引导词：what which whose when whet herif where
如：I think that you must work harder.
1. first aid 的意思是“急救”，例如：first aid to the injured 给予伤员的急救。
give/offer aid 援助 come to sb's aid 帮助某人
teaching aids 教具 medical aid 医疗救护
with the aid of 借助于
get injured 受伤，在现代英语中大量地出现了由“get + 及物动词不达意的过去分词”构成的被动语态，这叫 get -
The computer got (was)damaged when we were moving. 我们搬家的时候，电脑碰坏了。
Worried about the journey, I was unsettled for the first few days.
Well-known for their expertise, his parents’ company …..
Confused by the new surroundings, I was hit by the lack of fresh air.
Exhausted, I slid into the bed and fell fast asleep.
Heated , water changes into steam .
The professor came in, followed by a group of young people .
1 作原因状语，等于as / since / because 引导从句
Moved by what she said ,we couldn’t help crying . = ( As we are moved by
what she said …
2 作时间状语，等于when 引导时间从句，如果分词表示的动作与谓语的动作同时发生，可在分词前加when/ while / until
When heated , water can be changed into steam .
Seen from the hill ,the park looks very beautiful .= ( When the park is
seen from the hill…
3 作条件状语等于 if / whether 引导从句
Given more attention , the cabbages could have grown better .= ( If they
have been given more attention ….
Compared with you , we still have a long way to go = ( If we are compared
The actress came in , followed by her fans .
She sat by the window , lost in thought .
Much tired ,he still kept on working .=(Although he was tired ,) he ….
6 独立主格结构： 当分词的逻辑主语不是主句主语时，分词可以有自己独立的逻辑主语，这种结构称为独立主格结构。常用来表示伴随情况。
The boy rushed into the classroom , his face covered with sweat .
All things considered ,your article is of great value than hers .
Rewrite with proper conjunctions
Example : United we stand, divided we fall.
If we are united, we will stand, but if we are divided,we will fall.
1 Asked what had happened, he told us about it.
→When he was asked what had happened, …
2 Well known for his expert advice, he received many invitations to give
→Because he was well known for his expert advice, …
3 Given more time, we would be able to do the work much better.
If we were given more time,
4 Once translated into Chinese, the book became very popular among Chinese
Once it was translated into Chinese,
5 Deeply interested in medicine, she decided to become a doctor.
Because she was deeply interested in medicine,
6 Left alone at home, Sam did not feel afraid at all.
Although he was left alone at home,
Seeing these pictures, I couldn’t help thinking of those days when I was in
Beijing . Seen from the top of a thirty-storeyed building, Beijing looks more
Used for a long time, the book looks old.
Using the book, I find it useful.