John has finished his homework .we must do something to protect the environment.被动语态

问题描述:

John has finished his homework .we must do something to protect the environment.被动语态

John has finished his homework .John's homework has been finished by him.we must do something to protect the environment.Something must be done to protect the environment.被动语态 要怎么去理解啊先说 主动语态,就是谁 做了什么那么相对的,被动语态,就是 什么被谁做了那有什么格式的么?动词的形式分三种现在时,过去时,过去分词被动语态中,要用动词的过去分词的形式