"WHY NOT"可以等於"WHY DON'T YOU"或者"WHY DON'T WE"。例如，"Why not go for a walk?"可以改寫為"Why don't you go for a walk?"或者"Why don't we go for a walk?"。此外，"WHY NOT"也可以等於"HOW ABOUT"或者"WHAT ABOUT"。例如，"Why not have some coffee?"可以改寫為"How about having some coffee?"或者"What about having some coffee?"。