题目内容:
A.预告信号是间断鸣三次长声,即鸣30s、停、鸣30s、停、鸣30sB.准备信号是间断鸣一长、一短三次,即鸣20s、鸣10s、停、鸣20s、鸣10s、停、鸣20s、鸣10s
C.起爆信号是连续三短声,即鸣10s、停、鸣10s、停、鸣10s
D.解除信号是一次长声,鸣60s
参考答案:
B.准备信号是间断鸣一长、一短三次,即鸣20s、鸣10s、停、鸣20s、鸣10s、停、鸣20s、鸣10s
C.起爆信号是连续三短声,即鸣10s、停、鸣10s、停、鸣10s
D.解除信号是一次长声,鸣60s