keep on doing,keep doing ,keep sb doing用法的关联和区别

keep on doing,keep doing 一样的用法 保持（继续）做某事.
keep sb doing 使某人保持（继续）做某事
in order to do something 为了做某事 to 后跟 动词
in order that 后边跟 句子的
比如 I eat lots of apples in order that I will not feel thirsty.
其他的那些都很明显不是一个意思.没有区别的必要.