顺便说起某事，附带提及某事，怎么说英语呢？in passing

bca

我们都知道英语有个表达，by the way，简写 BTW，意思就是“顺便说起某事，附带提及某事”，这个的很明显的口语表达， 说话的人是“我”。如果要正式叙述这个表达， 比如记叙别人是顺便说起来的事情，可以用casually或者casual。英语学习者还需要明白另一个地道的说法。
in passing

mention / note sth in passing,  if you say something in passing, you mention it while you are mainly talking about something else
• 〔在谈论别的事情时〕顺便说起某事，附带提及某事:
»He did mention his brother's wife, but only in passing.
他确实提到了他的弟媳，但只是顺带而已。

in passing
   done or said while you are giving your attention to sth else
SYN   casually
   顺便；随便:
   He only mentioned it in passing and didn't give any details.
   他只是随口提及而已,并没有谈任何细节。

in passing:  in a brief way while discussing something else
She mentioned in passing that she was studying law.
The report notes the incident only in passing.
He mentioned in passing that a man named Kenneth Hansen was known in some circles to have committed the murders.