you don't know what
Du weißt nicht, was er mir angetan hat.
You don't know what he did to me.
Du weißt nicht, was ich da rede, oder?
You don't know what I'm talking about, do you?
— A Taxi Driver (2017)
Du weißt nicht, was ein Rocket Pencil ist?
You don't know what a Rocket Pencil is?
— The Garden of Sinners: Paradoxe Helix (2008)
You don't know what you're doing!