Unless in uniform, he doesn't look like a policeman.
除非穿上制服,要不他看起来不像警察。
what's his native language?
他的母语是什么?
Yes, and we must stop people walking on this floor until it's firm. It may be necessary to put up a notice saying Keep off. Another thing, we' ll have to drill a hole in the wall for the electric wires.