顾名思义，用来说明主句中谓语动词发生的目的的从句叫做目的状语从句。 表示目的状语的从句可以由 that(以便)，so that(以便)， in order that(为了;以便)，Lest(免得;唯恐)， for fear that(生怕;以免)等词引导;目的状语从句的谓语常含有may, might, can, could, should, would等情态动词。
例如：You must speak louder so that /in order that you can be heard by all.
He wrote the name down for fear that(lest) he should forget it.
Better take more clothes in case the weather is cold.
学习目的状语从句应注意以下两点：
(1)目的状语从句中常含有can,could,may,might,should等情态动词。 例如：
I got up early so that I could catch the first bus. 我起得很早，目的是为了赶上头班公共汽车。
(2)在口语中so可以引导目的状语从句。例如：
We"ll sit nearer the front so we can hear better. 我们坐的靠前一点，因此，我们听得清楚一点。
1、in order that与in order to的区别：
in order that+从句 in order to+动词原形 ( in order to后面加的那个不叫目的状语从句，叫目的状语) 例如：
He got up early in order to take the first bus.
= He got up early in order that he could take the first bus.(他起床很早是为了赶上第一班 公共汽车)
目的状语从句的一个特点：由于目的都是未来的行为，所以从句中一般用表示未来可能性时态，比如上面句中的could。当然还可以用will,would,can,等 。
2、so that既可引导目的状语从句，也可以引导结果状语从句。
1)其引导结果状语从句时，so that翻译为“以至于...”，经常可以和so/such...that...转换，且从句只能放在主句之后。如：He got up late so that he was late for school. = He got up so late that he was late for school.
2)其引导目的状语从句时，从句只能放在主句之后，此时可以和in order that换用。如：He got up early so that he could take the first bus. = He got up early in order that he could take the first bus.
