(一).You shouldn't have. 你不必这样。/让你白白受累了。
原音重现：

A: Here is a present for your birthday.
这是给你的生日礼物。
B: Thank you. You really shouldn't have.
谢谢，你完全不必破费。

美剧表达:

Oh, sweetheart, you shouldn't have, it's so beautiful!
噢，亲爱的，你不必这样的，不过它真的很漂亮。

(二).You are (very) welcome. 哪里哪里。/不客气。

原音重现：

A: Thank you for hosting the party.
感谢你举办这次派对。
B: You're very welcome. Come back again.
不客气，下次再来。

美剧表达:

I have some work to do. But you are welcome to stay.
虽然我有事情要忙。但请你随意。