radio distress signal

例句：

1. 1. The distress signal was pickedup by the rescue team.
   救援队收到了求救信号。
2. 2. They sent out a distress signalto alert other ships in the area.
   他们发出了求救信号，以警告该地区的其他船只。
3. 3. The pilot radioed for help afterlosing contact with the plane.
   飞行员在失去与飞机的联系后，通过无线电呼救。