so that,so as to,in order to 怎么区别?分别有什么用法?

in order to+动词原形和so as to+动词原形 都可以放在句中.She got up early in order to / so as to catch the first bus.她早早起了床以便赶上头班车 .The doctors gave her a general checkup so as to/ in order to find out the cause of her illness.医生给她做了全身检查,以便找出她的病因.in order to 可以放在句首,而so as to 则不可.In order to win the watch ,they practiced hard.为了赢得比赛,他们刻苦训练.In order to get good results,we ought to do our best to study the lessons.为了获得好成绩,我们应尽最大努力学好课程.2.so that 和 in order that 意思相同 “目的是 以便”引导目的状语从句
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.
3.so…that 和 such…that 如此..以至于..
结果状语从句常由so…that 或 such…that引导.so…that与such…that之间可以转换.例如：
The boy is so young that he can't go to school.这男孩年龄太小,不能上学.
He is such a young boy that he can't go to school