状语从句用作状语的从句叫作状语从句，其关联词是一些从属连词。
修饰主句中的动词、形容词和副词，通常由从属连词引导，按其意义和作用可分为时间、地点、条件、原因、让步、目的、结果、方式、比较状语从句等。
时间状语从句1) 常见连词有after,as,before,once,since,till,（not）until，when,whenever（no matter when），while，as long as,as soon as…例句：As you look at yourself in a mirror,you’ll seen an identical image of yourself.It is a long time before it is possible to test the medicine on human patients.It was not until…thatNot until…did he…Not until I received the letter,did I know he had gone to America.It was not until….When I got to the airport,I suddenly remembered that I had left the ticket behind.I was about to leave,when something occurred which attracted my attention.Whenever we have difficulty,he’ll come to help us.2) no sooner…than,hardly(scarcely,barely)…when: 刚做…就….No sooner had I opened the door than the telephone rang.She had scarcely news when she fainted.3) 还有immediately,directly,instantly,the moment,the minute,the instant,the second,every time etcI’ll tell you about it the moment you come.I got in touch with him immediately I received his letter.地点状语从句一般用where 或wherever 引导：I will stand where I can see the parade clearly.Wherever they went,they were warmly welcomed.条件状语从句真实条件从句:if,unless,so long as,provided that,supposing that,on condition that,in the event that,in case that etcI will not go to her party if she doesn’t invite me.I will not go to her party unless she invites me.原因状语从句从属连词有because,as,since,for,now,that,in that,seeing that,considering that(鉴于，由于)As the school regulations are written quite clearly,there is nothing more to be explained.Considering that the sweater was hard made,it was not expensive.Seeing that they are inexperienced,they are doing quite a good job.让步状语从句引导词分类：1): even if,though,even though,while(尽管) no matter what/how/which,however,whatever,whichever,however etc.He will not give up smoking even though the doctor advises him to.Whatever the consequence may be,I will be on your side.However hard she tried to explain,nobody trusted her.It has been the same result,whichever way you do it.2) 由as 引起的让步从句，语气较强烈，被强调的词须放在句首.Simple as the question may seem,it is not at all common in nature.Cold as it is,the children play outdoors.Much as I respect him,I can’t agree with him.Object as you may,I will go on with my plan.3) whether…or,不管…或…whether you be a student or a teacher,you are required to obey the regulations of the school.结果状语从句引导词：so that,so…that,such…thatHe is so humorous that we’ll never forget him.She is such a nice girl that everybody likes to make friends with her.目的状语从句引导词：so that,in order that,for fear that,lest,in caseI checked all the results time and again for fear that there should be any mistakes.Telephone us in advance in order that we might make the necessary arragements.方式状语从句引导词：as,(just) as…so…，as if,as though.1）as,(just) as…so…引导的方式状语从句通常位于主句后，但在(just) as…so…结构中位于句首，这时as从句带有比喻的含义，意思是"正如…"，"就像"，多用于正式文体，例如：Always do to the others as you would be done by.你希望人家怎样待你，你就要怎样待人。
