the old should be spoken to politely求翻译,其中副词前加to是

题目

the old should be spoken to politely求翻译,其中副词前加to是
什么用法?

答案

the old should be spoken to politely.被动语态
我们应该礼貌的跟老年人说话.
(we) should speak politely to the old.主动语态