on doing和upon doing是一样的吗?如果不是,

on doing和upon doing是一样的吗?如果不是, upon doing 用upon doing造句 continue doing和keep doing,go on doing是同义词组吗? 有decide doing sth.吗?为什么书上写decide on(upon) sth./doing sth.? on doing keep up doing 和insist on doing有什么区别 keep on doing 和keep doing 的区别 keep doing和keep on doing有什么区别 spend in doing 和 spend on doing的区别 是on doing so 还是in doing so 请问这里的upon doing是什么意思?I was already running, and upon reaching the car across the street...upon doing 是一个句型么?谢谢 13,appreciate doing sth 14,catch sb doing sth 15,consider doing sth 16,devote to doing sth 17,keep...doing sth 和 keep on doing sth 短语stay in , leave for,upon one's arrival on doing sth 什么意思? carry on doing与keep on doing keep on doing是坚持还是继续 decide on doing 对吗 carry on doing 造句