hit on/upon
1．discover or think of sth． by lucky chance偶尔发现；偶然想到
At last someone hit upon another road through the mountains．有人 终于发现了另一条穿山路。
The scientist experimented for a long time before hitting upon the solution to his problem.这位科学家经过长期实验才偶然发现这个问题的解决方法。
I hit on a good idea．我想出了一个好主意。
2. choose by chance碰巧选择
He hit on a business that was just starting to grow rapidly．他刚好 选择了一个正在开始迅速发展的 行业。