二、句型剖析

1.It+be+adj.+(that)从句

【相关链接】

【典型例句】

It will be useless learning a theory without practice.

学习理论而没有实践是没有用的。

It is not yet known where she has gone.

她去了哪里还不知道。

It is no harm drinking running water in that area.

在那个地区饮用流动的水质是无害的。

It is easier to say than to do.

说比做容易。

【知识小结】

it作形式主语时，没有具体意义，只是把真正的主语移后以平衡句子。

it作形式主语往往代替不定式、动名词和从句。

2.as+adj./adv.+as

【典型例句】

This ruler is as long as yours.

这把尺子和你的一样长。

Mary dances as well as kate.

玛丽舞跳得和凯特一样好。

He drove as fast as he could.

他尽可能快地开车。

She is as busy as a bee every day.

她每天都忙忙碌碌。

【知识小结】

(1)not as... as=not so... as

(2)as+adj.+a(an)+n.+as

(3)as+adj.+n.(pl.)+as

【相关链接】

(1)由as... as构成的习惯短语：

as... as possible　尽可能地

as... as sb. can　尽某人所能地......

as many/much as　多达......

as long as　长达；只要

as far as　远达；至于；就......而言

as well as　像......一样好；不仅；而且

(2)as... as结构可以用于倍数比较，倍数要放在as之前。

This room is four times as big as that one.

这个房间是那个的四倍大。

3.so/such... that...

【典型例句】

They are so hungry that they have to boil a pair of leather shoes in a pan and eat it.

他们如此的饥饿，以至于他们把自己的皮鞋放在平底锅里煮了吃。