IN ORDER THAT 为了...
譬如:He works hard in order that he may succeed.
他为求成功而拚命工作.
所以你这句话也应该填 IN ORDER THAT ,他为了他妈妈能下午收到所以早上寄出包裹.
so that引导目的状语从句时,表示“以便；为了”,从句中常使用can /could /may /might /will /would /should等情态动词或助动词；引导结果状语从句时,从句中一般不用can和may等词,在so that前可以用逗号,意思是“因此;所以”.
例句：
1、The little boy saved every coin so that he could buy his mother a present on Mother's day.（引导结果状语从句）
2、She bought a digital camera online so that she would save a lot of time.（引导目的状语从句）
这个解释应该能另你满意吧?