"Have you closed the shop?"
Translation:Dych chi wedi cau'r siop?
well this is dependant on dialect and first I'll explain the formal forms. Rydach chi is what I would say because I am from the north. Others would say Rydych chi. These to forms have resulted in two different informal forms in dach chi and dych chi. the course as of when I last tried doesn't seem to be accepting any answers with dach chi so carry on with dych chi for now when writing in the course.