"Was he here at six?"
Translation:Byl tady v šest?
I guess I never really considered that six o'clock is necessarily different from just saying six in English and I did get this wrong because I included hodin in my answer, but I think the point of being specific about this is to show us that they also sometimes say the hour without saying o'clock in Czech.
There is simply no reason, really. It actually is a lot of work to add unnecessary translations that someone might consdider "similar". It is not just "not accepting", it takes lots of manpower to add translations everywhere. To limit the necessary effort we have the Duolingo Golden rule.