"Are you going to be at your house tomorrow?"
Translation:¿Vas a estar en tu casa mañana?
Thanks for the reference. This is very useful and I will keep taking the quiz. One distinction I learned was SER for origin and ESTAR for location. Their mnemonic is SER for DOT (description, origin and time) and ESTAR for LoCo (location and condition).
At one point, I thought that Duolingo should supply this type of thing, but now I realize that the community/cloud help is part of their approach.