Questions & Answers about Ili demandas, ĉu uzi diapozitivon aŭ ne.
Yes. Demandi in Esperanto means to ask.
So Ili demandas = They ask.
This is a common false friend for English speakers. If you want to demand, Esperanto more often uses words like postuli.
Ĉu introduces a yes/no question, including an indirect yes/no question.
Here it means something like whether:
- Ili demandas, ĉu uzi diapozitivon aŭ ne.
- They ask whether to use a slide or not.
So ĉu does not mean who, what, or why. It signals that the issue is a yes/no choice.