1N-COUNT (飞机或船只遇险时发出的)无线电呼救信号 If someone in a plane or ship sends out a Mayday or a Mayday message, they send out a radio message calling for help because they are in serious difficulty. (飞机或船只遇险时发出的)无线电呼救信号
He raced to pick up the lifejackets while his stepmother sent out a Mayday call.
他的继母发出无线电求救信号的时候，他飞跑着去拿救生衣。
2CONVENTION （无线电求救信号中的求救内容）“求救！求救！” 'Mayday! Mayday!' is the phrase that is used in Mayday messages to indicate that help is needed. （无线电求救信号中的求救内容）“求救！求救！”