请问这是一句什么状语从句

题目

请问这是一句什么状语从句
You shouldn’t go rafting unless you know how to swim.

答案

条件状语从句
unless=if not
引导让步状语从句的连词主要有以下这些：though, although, as; even if, even though; whether...or...; no matter+疑问词,疑问词-ever.
条件状语从句
要点： 表示状语从句由连词if, unless (=if not) 引导.
1.If it doesn’t rain tomorrow, we will go hiking.
如果明天不下雨, 我们就去远足.
2.You will get good grades if you study hard.
如果你努力学习,就会取得好成绩.
3.I will go to the party unless he goes there too.
我不会去参加聚会的, 除非他也去.(如果他不去,我也不去.)
4.You will be late unless you leave immediately.
如果你不马上走,你将会迟到的.(=If you don’t leave immediately, you will be late.)