就是正在接电话的人说:“是我”
如果说你是Tom,你接起电话就说:“Tom's speaking”
楼主你那个Jack speaking写错了,应该是Jack's speaking。可能发音不好区分,可以理解…
意思就是现在是JACK和你通电话,通俗点就是……我是JACK
speaking 就是指说吧,隐含意思是……是我
意思是 Jack在听电话,是Jack在接电话
sb somebody缩写
sb speaking
就是 --这是某某在说话
比如this is tom speaking,who is that?
这是tom,你是谁?
(this is )Jack speaking, who is that?
这是Jack在讲话(我是jack),你是谁?