Why not let him pursue his studies as he likes?

"Do you think I should take that offer of a promotion?" " Why not? It's such a no-brainer ."

About the wedding ... It's a once-in-a-lifetime chance to be the main attraction, so instead of doing it on a shoestring, why not pull out all the stops and make a great show of it?

But why?

Why? Because his family needed the money, that's why.

Why? Because Terry Tate always replied promptly, that's why.

Do you? Why?

Why is the baby crying?

Heaven knows why.

Why are you in such a hurry?