顺便说

Could I just say in passing that … ?

能顺便说下…吗？

Incidentally, I think you still owe me some money.

顺便说, 想你还欠些钱。

By the way, the music at this event was played by a man with a cittern, who not only performed with virtuosity, but also with a sense of humour.

顺便说，活动的音乐是被人用西特琴奏的，不仅很艺术，而且感觉上有些幽默。