It's a guy thing.

这是男人的事。

A: I don't know why you like watching sports so much.
我不知道你为什么那么軎欢看体育节目。
B: It's a guy thing Women don't understand it.
这是男人的事，女人理解不了的。

I'll keep that in mind.

我会谨记的。

A: You should always do your best in life to succeed.
为了成功，你一生都要尽自己最大的努力。
B: That's good advice. I'll keep that in mind.
是个好建议，我会记住的。