"They will still be at school at 3 o clock"
same, I got it wrong.
Sep. 25, 2017 and it's still marked as wrong ...
In my opinion, there are many alternative ways of phrasing this e.g. "At three, they will be at school still."
At 3 o'clock they will be at school again?
Ещё means "still" or "yet". Again would be "ещё раз".