As for "Er (?)", Pei Yi's "Legendary Cui Wei" in the Tang Dynasty: "The female drinking messenger said: Cui Zi is going to Panyu, and she is willing to go there, and the messenger sings." It was also used in the Song Dynasty. In the description of Water Margin, there is "singing a song".
The Ming dynasty generally said "yes"
The Qing Dynasty's response to "zhē" is homophonic in Manchu, which means that as a response word, it is equivalent to "yes" and "good", but this word can only be used by Manchu officials and officials, but not by Han officials.