1、当as作介词时意思是“作为”，例句为：French is known as the most beautiful language in the world.意思为：法语以世界上最优美的语言著称 。
2、当as做关系代词时，引导定语从句，例句为：This is the same game as I played yesterday.意思为：这和我昨天玩的游戏一样 。
3、当as作连词时，引导原因状语从句时，所表达的意思为因为，例句为：As rain has fallen the air is cooler.意思为：因为下过雨，所以空气比较凉爽 。
4、当as作连词引导让步状语从句时，意思是“尽管 ， 虽然”，例句为：Young as he is， he has been one of the most famous painters in our country.意思是：虽然他还很年轻，但是已经成为我国最有名的画家之一 。
5、as做连词固定搭配as…as，例句为：My sister is as tall as me.意思是我姐姐和我一样高 。
【as的六种用法 as的用法总结7种】6、当然是作连词时，引导时间状语从句，例句为：My mom was cooking fish as I arrived home.意思为：当我到家时我的妈妈正在做鱼 。
