隔牆有耳

隔牆有耳(walls have ears,壁に耳あり障子に目あり,)
-----ge2 qiang2 you3 er3

例句: 小聲一點,小心隔牆有耳!
Xiao3 sheng1 yi4 dian3, xiao3 xin1 ge2 qiang2 you3 er3!
(Don’t speak so loud, walls have ears)