努力加油的英文是 "keep up the good work"，它的来源可能来自于一种对他人的肯定，表示肯定对方的努力和成绩。例如：

"Keep up the good work, I know you can do it!"

"努力加油，我相信你能行！"

"I'm really impressed by all the hard work you've been putting in. Keep up the good work!"

"你所付出的辛勤工作给我留下了深刻的印象。努力加油！"

"You're making great progress. Keep up the good work!"

"你的进步真是太棒了。努力加油！"