by chance
英 [baɪ tʃɑːns] 美 [baɪ tʃæns]
偶然，碰巧；意外地
例句
I saw the letter purely by chance.
我看见这封信纯属偶然。
I met him by chance out walking yesterday
我昨天外出散步时碰巧遇见了他。
Although we have only met by chance， I can see you are a very remarkable girl with a clear purpose in life.
虽然我们萍水相逢，可是我觉得你是个了不起的有志气的姑娘。
