as 用法归纳（对as用法的正确理解关系到阅读能力的提升）

as用法第1讲

首先，as可以作介词

as作介词用以表示“以...身份”或“当作”，后面跟有表示身份、职业、地位、人的特征的名词作宾语。

例如：

He worked as a slave.(He was a slave.)

He spoke as a lawyer.(He was a lawyer.)

比较：

He worked like a slave.(He was not a salve.)

He spoke like a lawyer.(He was not a lawyer.)

作介词的as常用来引入补足语：

（1）宾语补足语

例如：

They regarded him as their leader.

He looked upon it as certain.

I don't regard you as being dangerous.

We consider the writer as disconnected.

注：如果补足语是形容词或-ed分词，一般认为前面省略了being。

（2）主语补足语

例如：

The report was considered as false.

He is better known all over the world as Mark Twain.

常用语这一类结构的动词有如下一些：

acknowledge，define，describe，express，look upon，recognize，refer to,represent，serve，think of，treat，view，use等。

as用法第2讲

其次，as可用作副词

（1）表示同等程度、数量、质量等作“一样地......”解释。

例如：

He runs fast,but I run just as fast.(=I run just as fast as he does.)

Tom has a lot of money but I don't have as much.(=I don't have as much as he does.)

（2）用在形容词或-ed分词前。

例如：

man as different from other animals

man as described by scientists

as用法第2讲

再次，as可用作关系代词

（1）在the same...as“像......一样的......"和such...as”像......那样的......”结构中，as引导限制性形容词从句。

例如：

He is just the same as he used to be.

Such passengers as survived the explosion were drowned.

（2）as（=which）引导的非限制性形容词从句，可以出现在句首、句中或句尾。

例如：

She is a teacher,as is clever from her manner.

Water,as is known to all,is a liquid.

类似as you know的从句还有：

as everybody knows，as I see，as I have said，as I am told，as you may remember，as you may have heard，as you say等。

注意：区别形容词从句as seems和副词从句as it seems：

例如：

He is the best candidate,as seems possible.（as指主句）

He is the best candidate,as it seems.（it指主句）

as用法第2讲

小结：以上是关于as的三大用法小结，分别从as用作介词、副词和关系代词三个方面进行了小结，希望大家能够认真复习巩固。咱们下一期接着as用法的第2讲内容。

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