表示目的状语的从句可以由that, so that, in order that, lest, for fear that, in case等词引导。例如：
You must speak louder so that /in order that you can be heard by all. 你必须大点声，别人就能听见了。
He wrote the name down for fear that（lest） he should forget it. 他写下了这个名字以免以后忘记。
Better take more clothes in case the weather is cold. 最好多穿点衣服，以防天发冷。