A.安装 B.改造 C.重大修理 D.一般修理
A.门锁 B.门头 C.门靴 D.门导轨
A.0.6m/sB.0.8m/sC.1.5m/sD.3m/s
A.0.25M B.0.5M C.2M
A.0.2m B.0.3m C.0.4m D.0.5m