GEN     cuius   cuius   cuius             quorum quarum quorum

DAT       cui      cui       cui                 quibus  quibus   quibus

ACC     quem   quam     quid               quos     quas      quae

ABL       quo     qua        quo              quibus   quibus   quibus

These ask the specific questions who? or what?

ex:

Quis puerum vidit? Who saw the boy?

Quos vidimus?  Whom did we see?

Cuius fratrem vidimus?  Whose brother did we see?

Make sure you know the different forms for who in English!!!!