《剑桥高级学习词典》as词条，作conjunction时候，有这样一个例子：

This year, as in previous years, tickets sold very quickly.

 《牛津高阶英汉双解词典(简体) 第 8 版》as词条

在Adverb 词性，第2释义有这样的例子：

used to say that sth happens in the same way （指事情以同样的方式发生）和…一样

◆ The ‘h’ in honest is silent, as in ‘hour’. *honest 中的 h 与 hour 中的 h 一样都不发音。

然而，还是《牛津高阶英汉双解词典(简体) 第 8 版》as词条，后面出现了含糊其辞的内容：

 ASis a conjunction and an adverb and is used before a clause, another adverb or a clause beginning with a preposition. *as 为连词和副词，置于从句、另一副词或以介词引导的从句前：
◆ She enjoys all kinds of music, as I do. 她和我一样什么音乐都喜欢。
◆ Repeat these five steps, as in the last exercise. 照前面的练习一样，重复这五个步骤。

张道真《现代英语用法词典（重排本）》认为：

as作连词，可以(引起比较状语从句)像…一样地

跟一个作状语的结构（副词、介词短语等)： 

➢ There were only one-tenth as nnany drili breakages os before. (Mis)

➢ She trembled lest he might be as cold to her as formerly. (Dreiser)

➢ He was as much interested in music as ever. (Sinclair)

➢ There the tuberculosis rate is ten times as high as in North Carolina. (Foster)

➢ They have produced twice as much sugar as in the previous season. (Mis)

➢ I saw him as recently gj last March [as long ago as 1920]. (DCE)

➢ She can run as fast as 20 miles an hour. (DCE)

➢ I didn’t think she could run as fast as that. (DCE)

➢ He described the scene as vividly as if he had been there. (Eckersley)

➢ She is as clever as (she is) beautiful. (DCE)

网友可以对比各家观点，作出取舍。我个人倾向张道真前辈的解释。