让步状语从句是状语从句的一种：
让步状语从句 的常用引导词有：though,although,even if,even though,however,whatever,as等.
下面举几个例子,你就会明白了
even if 即使
We wouldn't lose heart even if we should fail ten times.
就是再失败十次,我们也不会灰心.
Whatever he does for her,he cannot please her.
无论他为她做什么,他都不能取悦于她.
Though he knows that he is wrong,he doesn't want to correct his opinion.
尽管他认识到了自己的错误,他还是不想改正自己的观点.
补充：
注意对让步状语从句的掌握要注意以下几点内容.
1) 使用though,although时,务必避免与but连用.
2) even if,even though和as if,as though不同.后者常常要求使用虚拟语气.
下面再举几个练习的例子：
例1、
I've already told you that I'm going to buy it,_________.
A) however much it costs B) however does it costs much
C) how much does it cost D) no matter how it costs
全句的意思是：“已经告诉过你了,不管花多少钱,我都打算买它”.空格应填上正常语序的让步状语从句,所以答案应该是A.B和C都是倒装,所以不对；D) no matter how应后接形容词或副词,所以D也不对.
例2、
________ the calculation is right,scientists can never be sure that they have included all variables and modeled them accurately.
A) Even if B) As far as C) If only D) So long as
即便计算是正确的,科学家们也无法肯定他们已经把所有的变量都包括进去并精确地模拟了它们.答案是A).