When I was a kid, my old English text book told me that we could response to "Thank You" with "Not At All", which means you are welcome. But when I answer two of my American friends with this phrase" NOT AT ALL" when they thanked me , in different times of course, they didn't quite know what I was talking about. After I told them everything about this phrase, they told me that that phrase could be used only when you don't accept someone's thank, that means you reject their thank unpolitely.
But in today's dictionary or some place, as well from Chinese friends' mouth, I could sometimes still get that phrase as "YOU ARE WELCOME".
How do you know about that, friends. Could you help me with that?
A lot of thanks to you guys.