use your head idiom (UK old-fashioned informal use your loaf)
（略有些生气地告诉某人）动动脑子
used to tell someone in a slightly angry way to think more carefully about what they are doing
Why didn't you use your head and cover the furniture before you started painting? 你为什么不动脑筋想想，在粉刷前把家具罩上？