英语翻译

题目

英语翻译
It's not essential that you do this at the start,but I am telling you this now
so that if you want to fill up your card before the course starts,that is what
I need to give you some money back.
求翻译这一段,尤其是that is what 这一句!它与前面那一句的关系是什么?

答案

起初您做这些不是必须的.但是现在我要告诉您的是.如果您想要在课程开始之前填写卡片,我就会回给您一些钱（这也就是我会回馈您一些钱）.