happen upon

偶然碰到(偶然发现)

例句与用法：

At the meeting I happened upon an old friend I had not seen for years.

在会议上我遇见了一位多年不见的老朋友。

词形变化：

动词过去式: happened | 动词过去分词: happened | 动词现在分词: happening | 动词第三人称单数: happens |