Can I have 20pounds cash back?

我可以提20镑现金么？

How would you like this cash back?

您要换成什么样的现金？

Do you do cash back?

你能不能退现金？

At the end of the term, you typically get no cash back.

固定年限到期后，你一般不会得到任何现金返还。

This can give you more money in the way of cash back.

这可以给你更多的钱在路上的现金回馈。