5、目的状语从句：that, so that, in order that

注意：目的状语从句的谓语动词常与情态动词连用，否则可能是结果状语从句。不可置于句首。

6、结果状语从句：that, so that, so … that, such … that …

注意：so + 形容词/副词 + that从句；such +名词 + that从句。

7、方式状语从句：as, as if(though)

I’ll do as I am told to.

It looks as if it is going to rain.

8、比较状语从句：than, as

9、条件状语从句：if, unless, so (as) long as, in case, once, a far as, on condition that.

注意if与unless的区别：不能用and连接两个unless从句，即不能有… unless …,and unless … 。但if … not and if … not却不受此限。

You won’t lose your weight unless you eat less and unless you exercise more.(×)

但可以说 … unless you eat less and exercise more.

10、注意状语从句中从句的省略现象

（1）连接词 + 过去分词

Don’t speak until spoken to.

Pressure can be incrased when needed.

Unless repaired, the washing machine is no use.