,. 一、主语表示法1、名词作主语David arrived last night. 大卫昨晚到达。
Pride goes before a fall. 骄必败。
2、代词作主语Who is speaking, please? （在电话中）请问您是谁？That's OK. 这没问题。
3、数词作主语Two will be enough. 两个就够了。
Two-thirds of the workers are women. 三分之二的工人是女工。
4、ing形式（动名词）作主语Skating is good exercise. 溜冰是很好的运动。
Looking up all the new words in the dictionary took him a lot of time.从字典里查所有的生词花费了他许多时间。
5、不定式作主语To translate this ideal into reality needs hard work.把理想转变成现实需要辛勤的劳动。
6、名词化的形容词作主语The blind and the lame are well cared,. for in our country.在我们国家，盲人和肢残人受到很好的照顾。
The unemployed usually lead a hard life.失业的人生活一般很困难。
7、短语（词组）作主语How to do well is an important question.如何把这件事做好是一个重要问题。
Early to bed and early to rise makes a man healthy.早睡早起身体好。
8、从句作主语What has happened proves that our policy is right.发生的一切证明我们的政策是对的。
Whether we'll go depends on the weather.我们是否去要看天气。
9、副词、介词短语作主语Slowly is exactly how he speaks. Between 8 and 9 will suit me.二、用it 作主语的句子,. （一）it 作人称代词1、代表刚提到的东西以避免重复Where is my book? ------ It is on the desk.2、代表抽象的事物It is very kind of you to help me.3、指某种动物Is this your dog? ----No, it isn’t.4、指未知性别的婴儿What a beautiful baby? -----Is it a boy?5、指彼此都知道的东西When did it happen?（二）it 作非人称代词1、指天气It is a fine day.2、指时间It is seven o’clock now.3、指距离How far is it from here to Guanzhou?4、指重量It is three jin altogether.5、指环境It is very crowded here in the weekend. （三）it 表示强调,. 强调句型：It is/was ……who/that……It was in the park that I met your father. It is you who I want to look for. （四）it 作先行主语(几种句型)1、be + 形容词+ 不定式It is very difficult to finish the job in time.2、be + 名词+ 不定式It is my duty to look after his children.3、be + 介词短语+ 不定式It is beyond me to say why.4、及物动词+ 宾语+ 不定式It takes me three days to finish the task.5、be + 名词+ 动名词It is no use saying too much about it now.6、be + 形容词+ 动名词It is worthwhile reading the novel. 7、其他结构It does’t matter making some mistakes.It does’t make any difference passing the exam.,. It felt funny dressing like that.（五）it 用于主语从句（常见的几种句型）1．It is a pity (a shame, a fact, an hono ur, a wonder, a good thing, good news , no wonder etc.) that …It is a pity that he can’t come. 2．It is strange (natural, surprising, ob vious, true, fortunate, good, wonderful , funny, ridiculous, possible, impossibl e, likely, unlikely, quite clear, unusual, e tc.) that …It is strange that he should know the answer.3．It seems (happened, thus came ab out, turned out, suddenly struck me, o ccurred to me, etc.) that…It seems that he doesn’t like this film.4．It is said ( reported, rumoured, ann ounced, arranged, decided, stressed, e xpected, etc.) that …It is said that he has been sent to America.5．It is doubtful (not known, not decid,. ed, not made clear, to be found out, tobe made clear, to be argued, to be dis cussed, to be decided,, being discusse d, being considered, a question, a mys tery, debatable, uncertain, open to qu estion, etc.) ＋连接代词或连接副词引导的从句.It is doubtful whether he will come next week.It was a question whether he should get married.It is not decided who will take part in the game.6.It does’t matter ( doesn’t make too much difference, doesn’t seem to matter much, does’t need to be bothered, doesn’t alter the situation, is of little consequ ence, doesn’t affect us, etc.) ＋连接代词或连接副词引导的从句.It doesn’t matter where we will go travelling.It makes no difference whether we go by train or by plane.,. （六）it 的其他用法1、可表示“是谁（在某处或做某事）Who is that? ------ It’s me.What is that noise? ------ It’s only the dog.2、泛指某件事It is my turn.It doesn’t matter.三、主语从句1. 由that引导：That price will go up is certain.That she is stiil alive makes us very happy.2. 由what引导：What you need is more practice.你需要的是更多的练习。
What I want to know is this.我想知道的是这一点。
What they are attacking is Marxism- L eninism itself.他们所攻击的是马列主义本身。
What is hard is to do good all one’s life and never do anything bad.难的,. 是一辈子做好事，不做坏事。
What little she said has left us much t o think about.她说的短短几句话很发人深思。
3、由连接代（副）词引导：Why she should have said such a thin g puzzled him.Whom we should send as our represe ntative remains to be discussed. When and where this took place is still unknown.Whether we should call this kind of se ntence elliptical is open to question. How she should word the letter troubl ed her greatly.Who is to take Xiao Zhou’s place as secretary is not yet settled. Whatever was said here must be kept secret.这里说的话都应当保密。
Whatever measures we adopt must be in conformity with the general line.我们采取的任何措施都应符合总路线。
Whoever sides with the revolutionary,. people is a revolutionary.什么人站在革命人民方面，他就是革命派。