Q: David hit Bill because Mary asked him to.
Who him is?
A: David

Q: In last week's tennis match, Djokovic imitated Roddick's serve because he was the better player.
Who he is?
A: Roddick

Q: Santa Claus and his elves distributed millions of presents worldwide to the children of the world, because they wish to reward those who behaved.
Who they is?
A:
Santa Claus and his elves