目的状语从句

 　　表示目的状语的从句可以由that, so that, in order that, lest¹, 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.

　　He wrote the name down for fear that(lest) he should forget it.

　　Better take more clothes in case the weather is cold.

1 lest   

conj.唯恐，以免

参考例句：

• Let me put down your telephone number lest I forget it.让我先记下你的电话号码，以免忘了。
• Be careful lest you fall from that tree.要当心，以免从树上摔下来。