短语词组短语bell cable signal cable 信号电缆jingle bell signal bell 信号铃block bell signal 闭塞铃信号bell and flasher signal 平交道警报器bell signal railway 是什么意思Signal bell 信号铃;信号钟;振零讯号;旌旗灯号铃signal alarm bell 信号警铃;告警铃 返回 bell signal