as作为关系词

This book is not such as I expect. We will give you such date _as_will help in your work. This isthe same tool as I used yesterday. he has as many books on information technology as I have. He is a man to whom work means as much as life.

关系代词： 这些句子中前面的such，the same，as many等相当于定语（第一句such为代词），as引导的定语从句修饰前面的名词，最后一句有些特殊，我觉得应该是个省略句，life后省略了means（有待证实）。

The size of the audience,as we had expected,was well over one thousand. As will be show in Fig. 5. As has been already pointed out. Internet access is very simple ,as indeed it is.

关系代词： 这个用法比较常见,最后一句中as指代了主句中的表语，并在从句中做表语成分，需要注意，但不影响理解。

He answered with the same simplicity as he asked.

关系副词： 上句中as作为关系副词指代with the same simplicity。

As引出状语从句

As a little girl she began to operate a computer. They will decide on their team as and when they qualify for the competition.

时间状语： as引导时间状语从句意为当···时，第二句中as and when表示一种不肯定的将来的事或行动。

As this problem is of great interest，we will discuss it once again.

原因状语： as当因为讲，可以换成Inasmuch as。

Old as he is, he dares the dangers of icy north.

让步状语： 使用时需要将句中的表语、状语或实义动词提前（原因状语从句也可能倒装，注意区分）。

as light as a feather

比较状语： 主要是as···as，注意上一句翻译为轻如鸿毛。

The letter reads as (what) follows. We must do as the doctor tells us. As two is to three, so is four to six. Do as (it) seems best.

方式状语： 注意主语的省略。固定搭配有：as···so···，···just as···，just as···，so···，much as···，as if（thought，注意使用虚拟语气）。