短语词组短语CCTV Display System 闭路电视显示系统cctv system schematic diagram 监控系统示意图cctv system of tunnel 隧道闭路电视系统Closed circuit television CCTV system CCTV 系统Data records of CCTV system 闭路电视资料记录CCTV and Alarm System Cables 闭路警报系统 返回 CCTV system