(1) the underground ::
地下(2) underground station ::
地铁站(3) underground train ::
地铁(4) underground water ::
地下水(5) underground railway ::
地铁(6) by underground ::
地下(7) go underground ::
隐匿(8) underground economy ::
地下经济(9) underground passage ::
地下通道(10) underground river ::
暗河