中科新闻网稀有陨石元素:~~关于过去完成时的一个小问题~~
来源：百度文库 编辑：中科新闻网 时间：2024/05/13 08:23:43
when 可不可以用在过去完成时里面？Why?
By the time I came in the classroom, they had already cleaned the classroom. 句中的by the time 能否用when代替？？？
谢谢！
Thank you for your answers!!!
By the time I came in the classroom, they had already cleaned the classroom. 句中的by the time 能否用when代替？？？
谢谢！
Thank you for your answers!!!
可以的!
可以