According to the video of Iqiyi, "Birds in pairs on the tree, green mountains and green waters are laughing" comes from the famous aria "Birds in pairs on the tree" in Huangmei Opera classic track "Fairy Couple", in which "Green mountains and green waters are laughing" comes from the ancient poem "Green mountains and green waters are laughing". This lyric depicts birds living in trees in pairs, and the green mountains and rivers are particularly beautiful in the sun, which makes people feel happy.