"What rivers do you know?"
Translation:Які річки ви знаєте?
Pronoun can be dropped in colloquial speech, but it's unlikely to be dropped in writing or in formal speech.
Things are getting more confusing the farther I get in the program. Earlier "what" = що, and "which" = як. So if in this exercise "what"= які, does that mean that що = which?
Maybe the the wrong English word was used in this exercise because the inquisitor is actually wanting to know which of all the rivers in the world the addressee has knowledge of. When I presented my 10 y.o. daughter with "__ rivers do you know" "what or which for the blank" she chose the word not in this exercise.