1．___________ to have been rich .

A .They say 　　　　　　 B. It is said 　　　　　 C .He is said 　　　　 D. He is said

如果选A，其后应接宾语从句。即：They say that he has been rich .如果选B ，其后应为主语从句。即：It is said that he has been rich .并且 “It is said that…”“据说…”这个主语从句结构可转化为单句，即：He is said to have been rich .因此答案为C。

6．用于强调句式中，it把一个简单句或一个主从复合句分开，分成两个小句．　

例如：

It was last night that I saw them in the theatre.

It is because he always gets up late that he is late for school.

It was not until the day before yesterday that they began to realize the importance of it.

　 [高考焦点]

5．作形式宾语代替不定式，V+ing形式或以that, whether / if引导的名词性从句，它们通常放在宾语补足语后面．这是宾语补足语通常是一个名词或形容词，而句子谓语常常是：believe, consider, feel, find, guess, imagine, know, think, suppose 等．

例如：

He found it important to study the situation in China.

They found it impossible to keep silent any longer.

He thought it a rule to do morning exercises every day.

They suppose it a duty to help others out of difficulties.

4．“It(形式主语)+谓语+主语从句”句型提要

(1)如果从句为主语的句子是疑问句，那就必须采用由it作为形式主语和句型结构。

例如：

误：Is that he told her everything probable? 正：Is it probable that he told her everything?

(2)it作为形式主语的句型有下列不同的搭配关系。如下表所示：

搭配关系

　 举例: It + be +形容词+主语从句　

　 　　　It is certain that William will do well in the exam.

　　 　　It is impossible that we (should) do two things at the same time.

当表语是important, necessary, strange等形容词时，主语从句的谓语动词常用“(should)+动词原形”的虚拟结构

It + be + 名词词组+主语从句　　　　 It is a pity that we can’t go.

　　 　　　　　　　　　　　　　　　　　It is a pity that he should refuse to accept the offer.

当结构表示惊奇、惋惜等感情色彩，通常在that分句中用虚拟语气

It + be + 过去分词 + 主语从句　　　 It is said that he has been in prison for two months.

It is suggested that each student (should) sing a song in English.

当it结构中的“be + 过去分词”中的过去分词是suggested, ordered, demanded等表示建议、命令、要求等意义的词时，that从句要用虚拟语气

It + seem (happen, etc.) +主语从句

　 It appears that they are in great need of food.

　　　 It happened that I had had some experiences in dealing with him.

　作形式主语代替不定式或v+ing形式及主语从句．

It’s pleasant to lie in the sun.　　　 　　　　 (To lie in the sun is pleasant.)　

It’s pleasing lying in the sun.　　　　 　　　 (Lying in the sun is pleasant.)　

It’s a shame that Tom is not here.　　 　　　 (That Tom isn’t here is a shame.)

3．做虚主语，没有实际意义，指天气，时间，温度，距离，潮汐，环境，现状等．

如：

It’s hot. 　　　　　　　　　　　　　　　　　　　　　　 It’s eight o’clock.

It’s raining.　　　　　　　　　　　　　　　　　　　　 It’s noisy outside.

另外可以和since连用：

It’s three years since we last met in Tianjin.

It was long since they had visited that computer factory.

　　　 　 与say连用:

　 　　It says there was a big fire in Hove. 　听说霍夫有一场大火．

与take连用：

　 It takes us half an hour to get to the railway station.

　　　 此外还有：It doesn’t matter.　 It is no use.

2．起指示代词的作用，指代一个人或物．

Who is knocking at the door? It’s me.

　 [要点归纳]it 的用法　

it 在句中作用多样繁杂，仅就常用的几种简述如下：

1．代替刚刚提到的事物：

　 　　　What’s this?　 It’s a book.

9．All the stories of families, heroes, wars and journeys are passed down from generation to　　　　 generation.

pass down　表示“传下来”的意思．

例如：

　 　　The skill has been passed down over four generations.

8．His newspaper provided him with some money in order that he might travel to Gambia for his research.

provide…with…给……提供.

例如:

They provided him with money, clothing and some other necessities.

in order that以便(后接目的状语从句＝so that所引导的目的状语从句)．　

例如：

I lent him $ 500 in order that he might go for a holiday.

7．On his arrival he was sold to a farmer and worked in the fields.

on his arrival 在他到达之际

on接v +ing的形式或接名词均可以表示在……时, 在……之后.

例如:

On reaching the city he called up his wife to pick him up at the airport.

On his return from Europe, he set to work at once.