The letter mentioned my great-aunt and uncle only incidentally.这封信只是附带提到了我的姑姥姥和姑姥爷。

requirements that really have little to do with their businesses, and only incidentally with their attempts to raise funds和他们的生意毫无关系、只是和他们的资金筹措沾边的要求

The tower, incidentally, dates from the twelfth century.顺便提一下, 这座塔要追溯到12世纪。

Incidentally, my shoulder feels a lot better.顺便说一下, 我的肩膀感觉好多了。