常用it作形式主语的句型结构

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。女口：

①It isquite certain that hewill be at the meeting.

②It is surprising that he came late to school this morning.

③It isimportant 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：

①It ishoped thatonedaytheywill haveenoughanimalsto setthem free

②It is well known that the earth goes around the sun.

③It 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：apity, anhonor, agood thing, afact, asurprise, goodnews, one's duty 等。如：

① It isapity (that)you missedthesportsmeetinglastweek.

② It isafactthatEnglish isbeingacceptedasaninternational 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：

①It seemsthat thereisabig wastepipecomingdown from the town.

T There seemsto be a big waste pipe coming down from the town.

②He appearedto becalm,but insidehisheartwasbeatingwildly with fear.

t It appearedthathewascalm,butinsidehisheartwasbeatingwildly with fear.

◊It does n't matter ( It 'no won der; It does n 'make much differe nee 等)

＋ when/ where/ which/ whether 等从句。如：

①Does it matterif hecan'tfinish thejob ontime?

②Theyareallclassmates. It isnowonder

they should help eachother with their studies.

◊It + be+ adj./ n. (for sb./ ofsb.)+ todosth. 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 fo r ；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 Jen'nys 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 hono，ur

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, sho等n 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,即pear, happe等） +主语从句，这类不及物动词有：appear, happe n, seei等, 如:

It seemed that he didn't tell the truth.

It happened that I was out when he called.