keep on doing 和keep doing 的区别是：用法不同、强调的内容不同
一、用法不同
1、keep on doing的用法：表示将一直在做的事继续做下去，通常只用 keep on doing。
例句：
He kept on working after dark. 天黑了他还继续干。
2、keep doing的用法：表示持续的状态或连续不断的动作(动作之间没有间隔)时, 通常只用 keep doing sth。
例句：
He kept standing during the meeting. 开会时他一直站着。
二、强调的内容不同
1、keep on doing强调“继续做某事”，动作之间略有间隔。
2、keep doing强调连续不断的动作或持续的状态 。
扩展资料
keep
读音：英 [kiːp] 美 [kiːp]
v.(使)保持，处于；继续，重复(做某事)；使耽搁；使延误
n.生活必需品;生活费用;城堡主楼
第三人称单数： keeps 复数： keeps 现在分词： keeping 过去式： kept 过去分词： kept
例句：
I managed to stick to the diet and keep off sweet foods...
我努力做到了只吃规定饮食，不沾甜食。
习语：
1、keep going（在身处困境或遭难时）尽力维持下去，坚持活下去 ；（用于鼓励）继续下去
2、keep sb going 足以使某人维持（或支撑）
3、for keeps 永远；永久
4、earn your keep 挣口饭吃；为有栖身之处而工作 ；值得所花的时间（或金钱）
keep on 更加强调时间的间隔性和动作的反复性,及某人做某事的决心.
keep doing坚持做某事
例句：
He kept talking until the meeting was over.他一直在说,直到会议结束.
He kept eating/ smiling/ walking.他一直在吃/笑/走.
She keep running她一直在跑（没停过）
He kept standing in the street .他一直站在大街上.
keep on doing 克服困难继续坚持
例句：
He kept on ringing me up,but I don't want to keep in touch with him any more.
他不断地给我打电话,可我不想和他保持联系了.
The boy kept watching the passing traffic at the gate.
这个男孩在门口不停地看着过往的车辆.
She kept on raising her hand她反复举手（不是一直举着手）
He kept on repeating these words over and over.他一遍又一遍重复这几句话.
本回答被网友采纳强调状语的继续,常与表示延续动作的动词与静止状态的动词连用,如(hope,think,wonder,dream,sit,stand,lie,sleep等)
He kept talking until the meeting was over.他一直在说,直到会议结束.
He kept eating/ smiling/ walking.他一直在吃/笑/走.
She keep running她一直在跑（没停过）
He kept standing in the street .他一直站在大街上.
keep on doing 表示动作反复,强调动作与动作之间有间隔,常与表示短暂动作的动词连用.“坚持做某事”,克服困难继续坚持.
He kept on ringing me up,but I don't want to keep in touch with him any more.
他不断地给我打电话,可我不想和他保持联系了.
The boy kept watching the passing traffic at the gate.
这个男孩在门口不停地看着过往的车辆.
She kept on raising her hand她反复举手（不是一直举着手）
He kept on repeating these words over and over.他一遍又一遍重复这几句话.
1) 均可表示“继续做某事,反复做某事”,可互换,只是 keep on 更加强调时间的间隔性和动作的反复性,及某人做某事的决心.
He kept on working until midnight though he was tied.
The boy kept /kept on asking some silly questions in class.
2) 若表示一连续不段的动作,或某一动作的持续状态,只宜用keep doing .
She kept waving to her husband until he was out of sight.
They kept standing outside the room during all the meeting.
Keep lying here; I will be back soon.
3) 若表示今后或将来继续做某事,则只宜用keep on doing .
We must keep on working hard in the coming new year.
He kept on smoking though we advised him to stop to smoke.本回答被提问者和网友采纳
1) 均可表示“继续做某事,反复做某事”,可互换,只是 keep on 更加强调时间的间隔性和动作的反复性,及某人做某事的决心.
He kept on working until midnight though he was tied.
The boy kept /kept on asking some silly questions in class.
2) 若表示一连续不段的动作,或某一动作的持续状态,只宜用keep doing .
She kept waving to her husband until he was out of sight.
They kept standing outside the room during all the meeting.
Keep lying here; I will be back soon.
3) 若表示今后或将来继续做某事,则只宜用keep on doing .
We must keep on working hard in the coming new year.
He kept on smoking though we advised him to stop to smoke.