英语语法：keep doing sth.继续做某事 该如何理解其句子成分?keep理解成系动词?donging是动名词作

英语语法：keep doing sth.继续做某事 该如何理解其句子成分?keep理解成系动词?donging是动名词作 保持做某事 只有keep on doing sth.有没有keep doing sth.或keep to do sth. 第二个的中,keep doing =keep on doing =继续 做某事是不是? 请问keep on doing和 keep doing在用法上有什么区别?还有,当表示“继续做某事‘时,keep on 英语动词问题动词后面加不定式 或动名词有什么规律吗 比如keep doing sth keep on doing sth keep on doing是坚持还是继续 keep doing somethingd 用法和理解 keep+doing后面doing是动名词还是现在分词? keep sb doing sth中的doing sth是宾语补足语还是与keep构成系表结构的表语? keep doing和keep sth do keep+sb/sth+形容词?keep+doing