According to Baidu Encyclopedia, "lingering sound" is a metaphor for beautiful songs or music, as well as meaningful and intriguing poems; As predicate, attribute and object; With praise. This idiom originated from fable and was first published in Liezi Tang Wen.
Application example of reverberation around beam;
1, Shang Song Ouyang Xiu, Poetry in the Wine Garden: "As far as narration is concerned, the whole text ... I am sorry for what I said, and I don't have any lingering meaning."
2. Liu E's Travels of Lao Can, the second time: "When I was studying, I saw the ancients describing the benefits of singing. If there is such a saying as' lingering for three days', I have never understood it ... I didn't know the quip of the ancients until I listened to Mr. Xiaoyu's story. "