状语从句在主从复合句中修饰主句中的动词、形容词或副词等，按意义可以分为时间、地点、原因、目的、结果、条件、方式、比较、让步等状语从句。
六.让步状语从句。
1.由however, whatever, whenever, whoever等引导，相当于no matter how/what/when/who 等。例如：
We’ll have to finish the job,_____. (NMET99)
A. long it takes however B. it takes however long
C. long however it takes D. however long it takes
答案： D. however 是副词性引导词，必须直接位于所修饰的形容词long之前，并放在句首引导状语从句。
应该注意：however, whatever, whenever, wherever 等还可以引导名词性从句，而no matter how, no matter what, no matter when, no matter where等只能引导状语从句。例如：
Whatever I said couldn’t cause his interest in the topic.
2.由though, although, as, even though/if 等引导让步状语从句，不能与 but 连用，但可于yet连用。
(1).由as引导的让步状语从句，必须倒装表语形容词、名词(前面不用冠词)或者副词状语或者动词原形，though 引导的让步状语从句可以倒装，也可以不倒装，而although引导的不能倒装。例如：
He didn’t light the fire though/although it was cold.
Although he is very old, (yet) he still jogs every day.
Rich as/though he is(=Although he is rich), I don’t envy him.
Difficult that task was, they managed to finish it in time.
Child as he is, he knows a lot.
Much as I love it, I’ll not buy it.
Try as they may, they won’t succeed.
(2).even if, even though 表示“即使，纵然”，有退一步设想的意味，多用于书面语中。
例如：
I’ll do it, even if it takes me all the afternoon.
Even if he did say so, we can not be sure that he was telling the truth.
(3).whether(…or)引导让步状语从句,提供两个或两个以上供选择的条件。注意此时的whether不能换成if. 例如：
Whether he drives or (whether he) takes the train, he’ll be there on time.
七.条件状语从句
条件状语从句用if, unless, as/so long as, on condition that, provided, providing, now that, in that 等引导。除了应注意这些词的语义差别之外，还需注意，在条件状语从句中不能用将来时，只能用一般现在时表示一般将来时。例如：
If China becomes strong and powerful, we’ll never bully other countries.
As long as we don’t lose heart, we’ll turn our dreams into realities.
He won’t believe anything unless he sees it with his own eyes.
I will lend you the money on condition that you pay it back in one month.
有时if 条件句中也用will, 但此时用来表示主语的意愿。例如：
If you will come to work in our city, I’ll try my best to meet your demands.(如果你愿意来我市工作，我将尽力满足你的要求。)
八.方式状语从句
1.方式状语从句用 as, just as, as if, as though 引导。
2.关于方式状语从句值得注意两点：
(1).as 表示行为方式;
(2).在打比方与事实相反或不可能实现时，as if /though 引导的从句用虚拟语气。但当句子谓语为过去时态时，特别是当句子谓语为look, seem, taste, smell等感官动词时，从句谓语动词不用虚拟语气。例如：
I have changed the plan as you suggested.
When at Rome do as the Romans do.(入乡随俗)
I have loved you as if you were my own son.
It looks as if it is going to rain.
九.比较状语从句
比较状语从句常由than, as…as , not so/as…as, the more…, the more …等引导。例如：
He didn’t do as much as he had promised.
I know you as well as any member of your family.
Now we can produce much more steel than Japan.
The longer you stay with him, the better you will know him.
