to have been doing 和 having been doing 有什么区别,重点是have 和having

前一个是即将做,还没做.而后一个是做过了的意思.这种语法现象适用于各种地方
再问： 那having been doing 和 having been done呢？有什么区别，有点搞混，求举个例子
再答： having been done 是现在完成时的被动语态，having been doing 是现在完成进行时，表示动作从过去发生并且持续到了现在。例子：I have been doing my homework since yesterday.
I have been asked many questions by my friends.