The girl studies very hard so that she gets a high mark in the exam. 这个女孩学习很用功，这次考试就得了高分。

so that引导结果状语从句，从句中一般不用情态动词。

The girl studies very hard so that she may (in order that she might) get a high mark in the exam. 这个女孩学习非常用功，为的是能在这次考试中得高分。

so that引导目的状语从句，从句中一般用情态动词。

so that引导结果状语从句，有时也带情态动词或在so that前面加逗号或分号

He spoke slowly and clearly so that everyone could hear. 他讲得又慢又清楚，人人都能听得到。

He went early, so that he got a good seat. 他去得很早，得了个好座位。