衛(wèi)生類職稱英語(yǔ)考試語(yǔ)法：

“It”的用法

1.代詞it

（1）指除人以外的一切生物和事物。如：

I hope it was as good as the one you lent me.

I knew at once that it was a gift from Father.

The more carbon the steel contains, the harder it is.

（2）在某種情況下代詞it也可以指人。這時(shí)可把it看作指示代詞。如：

Is it your brother?

I didn't know it was you.

"Oh? who was it?" Mr.Black asked.

（3）it用來(lái)表示自然現(xiàn)象、時(shí)間、距離等。如：

It is nine sharp now.

It is very hot today.

It is far to the airport.

2.it 作形式主語(yǔ)

（1）做不定式的形式主語(yǔ)

It's nice to be with you.

It's not easy to get him to change his mind.

Is it possible to go by bike?

（2） that…句的形式主語(yǔ)

It's true that she's ill.

It seems obvious that we can't go on like this.

It occurred to me that she might have forgotten the date.

It doesn't interest me whether you win or not.

It doesn't matter when you arrive — just come.

It wasn't very clear what she meant.

It's surprising how many unhappy marriages there are.

（3）作動(dòng)名詞的形式主語(yǔ)

It was nice seeing you.

It's unusual her going off like that.

It's no use trying to explain—I'm not interested.

3.it作形式賓語(yǔ)

如果一個(gè)帶有賓語(yǔ)補(bǔ)足語(yǔ)的動(dòng)詞不定式做賓語(yǔ)或一個(gè)賓語(yǔ)從句太長(zhǎng)，可以用it作該不定式或賓語(yǔ)從句的先行詞——形式賓語(yǔ)。如：

George made it clear that he disagreed.

She thinks it easy to understand a letter written in English.

She found it difficult to get along with him.

He felt it his duty to help her.

4.用于強(qiáng)調(diào)結(jié)構(gòu)中的it

這種結(jié)構(gòu)的句型是：It + is（was） + 被強(qiáng)調(diào)的部分 + that（或who）+ 其他部分。如：

It is the force of gravity that makes heavy things fall toward the ground.

It is from the sun that we get light and heat.