短語詞組短語distress radio frequency 遇險無線電頻率radiotelephone distress frequency 無線電話遇險頻率DF Distress Frequency 求救頻率international distress frequency [水運(yùn)][通信]國際遇險呼救頻率;國際遇險頻率;國際危難呼救頻率;繙譯radiotelegraph distress frequency 無線電報遇險頻率radiotelephone distress frequency watch 無線電話遇險頻率值班telephone distress frequency 無線電話遇險呼救頻率idf international distress frequency 國際遇險呼救頻率international boundary distress frequency 國際遇險呼救頻率 返回 distress frequency