谁能了解一下现在完成时的用法

问题描述:

谁能了解一下现在完成时的用法

一般形式:have done表示现在的过去,已经完成的动作被动语态:have been donee.g.
非被动语态:I've finished my homework被动语态:
My homework has been finished by me.采纳哦