so that 后面是加的完整的句子。

in order to 后面加动词原形。

I got up early in the morning so that I could catch the first bus to school.
I got up early in the morning in order to catch the first bus to school.

此外同样表示“为了”的意思的还有：
so as to 后面接动词原形,表示结果.
so that后面接从句,表示结果.
in order to 后面接动词原形,表示目的.
in orde that后面接从句,表示目的.