Why do you do that

so as not to miss the first bus.

in older not to miss the first bus.

　　so that也可用来引导结果状语从句。在so that引导的结果状语从句中，谓语动词前不用情态动词，主从句间可有逗号隔开。例如：

Everyone said no, so that the plan was dropped. 大家都反对，计划就不再讨论了。

　　cut down, cut in, cut off与cut out的区别

　　cut down意为砍倒，削减，指将树砍倒或裁军

　　to cut down a tree with an axe 用斧头把树砍倒

　　cut in 意为打断，指从语言中打断

　　Don't cut in while I'm talking. 我说话时别插嘴。

　　cut off意为“切断、切下”指切断电源，水源，煤气等。

　　He cut off the gas when a fire breaks out.

　　cut out意为切下，删下，指删掉，剪下文章等。

　　He cut out an article from the newspaper.