A、遇險/安全 B、遇險/全呼 C、全呼/安全 D、全呼/遇險
A、Distress/distress B、allship/Distress C、Distress/ALL ship D、All ship/All ship
A、呼叫序列 B、應(yīng)答序列 C、應(yīng)答方 D、B和C