当as引导限制性定语从句的时候，as的作用是关系代词和关系副词。As在从句中可以充当主语、宾语、状语或表语等；当as引导非限制性定语从句，as主要用来指代整个主句。
扩展资料
My new job is much the same as the old one.
我的新工作和旧工作差不多。
Take as much time as you like.
你想花多少时间就花多少时间。
Research will be needed as a preliminary to taking a decision.
作出决定之前需要进行研究。
This years results are virtually the same as last years.
今年的结果几乎和去年的.一样。
Its not so easy as youd think.
不像你想的那么容易。
