"He is hungry, and no one has served him yet."
Translation:Il a faim et personne ne l'a encore servi.
The first time round I said "...personne ne lui a encore servi" and was marked wrong. Maybe there is a subtle difference, although I just found "Oui, je lui ai servi de la nourriture, puis" in Reverso.
Aha! When there is an object you'd use lui perhaps. You serve food to him in French, but "You serve to him" on its own wouldn't make sense. I think I just answered my own question. Come to think of it, it's the same in English.
It's a bit complicated. If the served thing (or whatever) is present, the receiver is an indirect object. Otherwise the receiver is a direct object.
Ce monsieur-la? Je vais le servir tout de suite: je lui sers d'abord la soupe qu'il a commandée. [stupid sentence with both cases]
So we learned about "personne ne ..." for no one, and "ne ... pas encore " for yet. Therefore, I answered "Il a faim et personne ne l'a pas encore servi", and was marked incorrect since apparently there should not be a 'pas' here. However, I am wondering why since I would think that 'yet' translates to 'ne ... pas encore'. I would think that "personne ne l'a encore servi" would mean 'no one served him again'.