He has been running since l came.---------------(对画线部分提问)---- --- --- he---- running?这是现在完成进行时,应该如何提问?how long好像不适用吧.

问题描述:

He has been running since l came.
---------------(对画线部分提问)
---- --- --- he---- running?
这是现在完成进行时,应该如何提问?how long好像不适用吧.