他在去北京之前已经学过中文怎么写?He has learnd chinese before he came to beijing.
问题描述：
他在去北京之前已经学过中文怎么写?He has learnd chinese before he came to beijing.
我记得before出现用一般现在时,但before 引导的句子主句和从句时态是什么?
答
对的,我刚学完.新概念弟2册14课有