by the way 附带/顺便说一下（用于转入与之前主题无关的事）

【例句】
By the way, I found that book you were looking for.
顺便提一下，我找到了你在寻找的那本书。

The Kunlun Hotel has some very nice bathrooms, by the way, and I got to know them well during this period.
昆仑饭店有一些非常舒适的洗手间，顺便说一下，就是那段时间我才知道的。