用来修饰谓语动词、其它动词、定语、状语或整个句子的从句叫做状语从句.状语从句从其表达的意思上可分为：时间状语从句,地点状语从句,原因状语从句,条件状语从句,目的状语从句,让步状语从句,比较状语从句,程度状语从句,方式状语从句,结果状语从句十大类.
1.让步状语从句常由although/though（虽然）,even though/even if（尽管）,as（尽管）引导
Although she slept ten hours last night, she is still tired.虽然她昨天睡了十个小时,但她仍然很 累.
2.方式状语从句常由as if/as though（好像,如同）等引导.
She acted as if/though nothing had happened.她表现得似乎什么事情也没发生过一样.
3.条件状语从句：一般由if（如果）,unless（除非,如果不）,as/so long as(只要)等连词引导.
Unless you study harder,you're going to fail the exam.如果你不努力,你考试将会失败!
