When talking,they sat face to face with each other.起中后when为什么用talking
问题描述：
When talking,they sat face to face with each other.起中后when为什么用talking
when talking,这是怎么一个用法?talking在这里是什么成分?
答
when引导的时间状语从句中 如果主语和主句一样且谓语动词为be时 就可以省略从句成分 如原句可以是When (they are) talking,they sat face to face with each other