碰运气英语怎么说

碰运气的英文表达是 "to rely on luck" 或 "to leave it to chance." 来源可能源自人们对幸运的信仰，例如抛硬币决定事情、开运气汤圆等。例句：
I'm not going to rely on luck to pass the exam, I'm going to study hard. (我不打算靠运气通过考试，我会努力学习的。)
If you leave it to chance, you might win the lottery, but it's not very likely. (如果你靠运气，你可能会中彩票，但不大可能。)