英语语法分析

He raced to pick up the life jackets while his stepmother sent out a Mayday call.

他的继母发出无线电求救信号，他飞跑着去拿救生衣。

《柯林斯英汉双解大词典》

For decades, MayDay parades in Moscow have taken place under clear blue skies, aircraft having deposited dry ice, silver iodide and cement powder to disperse clouds.

几十年来，莫斯科的五月节游行都是在晴朗的蓝天下举行的，他们飞机上撒下干冰、碘化银和水泥粉来驱散云层。

Apparently, no mayday call was issued.

显然，没有发出求救呼吁。