偶然遇到：指无意中遇到或发现某事物。
碰巧发现：指意外地发现或遇到某事物。
happen on //
动词 to find by chance 偶然找到
I happened upon a five-pound note lying in the street
find unexpectedly
同义词： fall upon / strike / come upon / light upon / chance upon / come across / chance on / attain / discover
... chance on 碰巧遇见 happen upon 偶然碰到(偶然发现)... run across 偶然遇见(不期而遇)...
... happen unexpectedly 发生意外 happen upon 偶然发现 how it happen 真相大白 ...
Luck doesn't just happen upon us.
运气并不会碰巧降临在我们身上。
How do you happen upon these subjects?
您是如何想到这些主题的？
Our heroes happen upon a Bug pokemon Catching Contest.
我们的英雄时发生错误神奇宝贝赶超竞赛。
Just as your lover's caress brings you to orgasm, your eyes happen to fall upon a shoe.
正当情人的爱抚使你进入高潮的时候，你的目光恰巧落在了鞋子上。
心理学导论课程节选 : 耶鲁公开课
An investigator couldn't just happen upon it as part of a general trawl for allegations against Savile.
As Sonny and his mother (played by June Carter Cash) are driving down the highway, they happen upon a multi-car accident.
CNN: Review: Praise the Lord and pass the editing console for 'The Apostle'
Fortunately, the case of Mvscles and Muscles is merely a strange occurrence when people oceans apart happen upon a few seconds of pop panache that sound eerily similar.
FORBES: Boston Electronic Duo Mvscles And The Case Of Musical Coincidence