1、 1.第一种：As可以引导定语从句.有时可译为“正如”.此时,常常是as从句在前,主句在后。例如：As we can see,he is a Chinese. 2、 2.第二种：As 还可引导原因状语从句,“因为,由于“。例如：As he is so lazy,he never cooks by himself. 3、 3.第三种：As还可引导时间状语从句,“当,随着”。例如：As the weather is colder and colder,the leaves of the tree is less and less. 4、 4.第四种：As还可引导方式状语从句,“按照”。例如：You must do the work as I have told you.