! When there is a limited number of possible things or people, usewhich:Which leg (NOT what leg) did he break?|It was one of his sisters. I can't remember which (NOT what).
2used to introduce aclause about something that is or was not known or not certain:
No one knows exactly what happened.
It is not clear to what extent these views were shared.
b) alsowhat of ...?formalused to introduce a new subject into a conversation, or to mention something or someone else that also needs to be considered:
What about Patrick? What's he doing nowadays?
What about me? Aren't I coming too?
So that's the food - now what about the wine?
And what of her other job? How is that progressing?