常用it作形式主语地句型结构

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常用it作形式主语的句型结构 ◇ It + be +形容词+ that-从句

可用于此句型的形容词有: wonderful, true，good，right，wrong，（un）important，useless，surprising，clear，unusual，lucky，certain, necessary等。如： ① It is quite certain that he will be at the meeting.

② It is surprising that he came late to school this morning. ③ It is important that we (should) study hard

注意: 该句型中的形容词是（un）important, necessary等时，从句应为 (should )+动词原形。 ◇ It + be + -ed 分词+ that-从句

适用该句型的过去分词主要有: said, reported, announced, hoped, thought，told，believed，expected，decided，suggested, known等。如：

① It is hoped that one day they will have enough animals to set them free ② It is well known that the earth goes around the sun.

③ It is suggested that the sports meeting (should ) be put off until next week. 注意: 该句型的过去分词是suggested时，从句应为 (should )+动词原形。 ◇ It + be +名词+ that-从句适用该句型的名词（词组）有: a pity，an honor，a good thing，a fact，a surprise，good news, one’s duty等。如：

① It is a pity (that) you missed the sports meeting last week.

② It is a fact that English is being accepted as an international language. ◇ It ＋seem／ appear／ happen的适当形式＋that从句。该句型常可以转换成含不定式的简单句。如：

① It seems that there is a big waste pipe coming down from the town. →There seems to be a big waste pipe coming down from the town.

② He appeared to becalm, but inside his heart was beating wildly with fear. →It appeared that he was calm, but inside his heart was beating wildly with fear. ◇ It doesn't matter ( It’s no wonder; It doesn’t make much difference等) ＋ when/ where/ which/ whether 等从句。如： ① Does it matter if he can't finish the job on time ② They are all classmates. It is no wonder

they should help each other with their studies.

◇ It + be + adj./ n. (for sb. / of sb.) + to do sth. 该句型中的形容词通常是表示事物的特点或特征的如difficult，hard，easy，impossible，necessary，important等，此时用for；或表示人的性格特征或特点的如nice，good，bad，kind，silly，foolish，wise，clever， careless，rude，brave，cruel，careful， grateful等，这时要用 of。如： ① It is foolish of you to give up such a good chance.

② It is necessary for college students to master at least a foreign language

It作形式主语常见句型

动词不定式，动名词或主语从句作主语时，通常把它们放在谓语动词前，而用it作形式主语，放到句首，常见句型有： 1. It + be + 形容词+主语从句，如：

It is uncertain whether he can come to Jenny’s birthday party or not. 2. It + be + 名词词组 + 主语从句，这类名词有：a fact, a pity, a shame, an honour，a question等，如：

It’s a pity that you missed the exciting football match. It remains a question whether he will come or not.

3. It + be + 过去分词 + 主语从句，这类过去分词有：announced, believed, expected, hoped, decided, reported, said, shown等，如： It is reported that 16 people were killed in the earthquake. It is not decided who will give the operation to the patient.

4. It + 不及物动词(seem, appear, happen等) + 主语从句, 这类不及物动词有：appear, happen, seem等，如： It seemed that he didn’t tell the truth. It happened that I was out when he called. 5. It + be + 形容词 + for sb.）+ 动词不定式

这类句型常用形容词easy, difficult, hard, important, possible，wise等作表语，有时候为了强调不定式动作的执行者，常在不定式前加for sb，如： It’s necessary for the young to master two foreign language. It is unwise to give the children whatever they want.

这类形容词有：easy, difficult, hard, important, possible，wise

6. It + be + 形容词 + of sb. + 动词不定式，这类形容词常是表示心理品质,性格特征的形容词，如：kind, nice stupid, clever, foolish, polite, impolite, silly, selfish, considerate等。某人和这些形容词可以构成主系表结构。如：

It’s very kind of you to help me with the work. =You are kind to help me.

It seemed selfish of him not to share his dictionary with others. =He seemed selfish not to share his dictionary with others. 7. It + be +名词词组 + 动词不定式，如： It is not a good habit to stay up too late.

8. It + be + 名词或形容词 + 动名词，这类名词和形容词常常是：good, no good, no use, a waste of, useless, senseless等，如： It’s a waste of time talking to her any more. It is no use arguing about the matter with him.

9. It + take ( sb. )+ 时间（金钱）+ 动词不定式，如： It took the workers almost three years to finish building the dam. It will take a whole day to get to the top of the mountain on foot. 实战演练：

1. It is generally considered unwise to give a child he or she wants. (NMET 1997)

A. however B. whatever C. whichever D. whenever

2. In fact is a hard job for the police to keep order in an important football match. (2001 上海)

A. this B. that C. there D. it

3. is a fact that English is being accepted as an international language. (NMET1995)

A. There B. This C. That D. It

4. Is necessary to take off our shoes when we enter the lab (MET88) A. everyone B. this C. her D. it

5. ________ will take you a lot of time to find him in the crowd. A. It B. I C. We D. They

6. It is no use his _________ there, the situation is hopeless now. A. to go B. to be going C. going D. having gone 7. It is never too late to learn, ________

A. is it B. isn’t it C. does it D. doesn’t it

8. ___________ is known to all that Shenzhou VI Launched Successfully. A. As B. What C. It D. That

9. _______ is reported in the newspaper, the Earthquake in east China's Jiangxi Province killed 13 people

A. It B. As C. That D. What

10. ___________ certain that his invention will make people’s life convenient. A. That’s B. This is C. It’s D. What’s

11. _________ that there is another football match on the air this evening. A. It says B. It was said C. It is said D. What was said

12. __________ that their daughter got an opportunity to study abroad. A. It’s a exciting news B. This is an exciting news C. This is exiting news D. It’s exciting news 参考答案：

1——5 BDDDA 6——10CACAC 11——12CD

一、主语从句的概念与类型

主语从句在复合句中作主句的主语,引导主语从句的词有从属连词that, whether以及连接代词who, what, which, whoever, whatever, whichever和连接副词when, where, why, how等.例如:

That she was chosen made us very happy.她当选了使我们很高兴.

What caused the accident is a complete mystery.是什么导致了这次事故还完全是一个谜.

Whether she will come or not is still a question.她是否来还是一个问题.

Which team will win the match is still unknown.哪个队会赢得这场比赛还不知道.

Whoever comes to the party will receive a present.参加聚会的每一个人都将收到一份礼物.

When they will start has not been decided yet.他们何时出发还没决定.

注意:上述例句中的主语从句都是放在句首,但有时为了使句子结构平衡,避免\头重脚轻\常用it作形式主语,而把从句放在后面.例如:

It is a pity that she has made such a mistake.她犯了这样一个错误,真是遗憾.

It depends on the climate whether they are going shopping today.他们是否今天去购物还得看天气情况.