I'm sorry, but I cannot find the lyrics for the song "Happily Delivering The Public Grain" in the pipa grade 6 textbook. This song is a folk instrumental piece composed by Gu Wuxiang and Meng Jinjin in the 1970s, depicting the scene of farmers delivering the public grain after a harvest[^2^] [^3^]. It is a complex three-part form, consisting of an introduction, a flourish, and a conclusion[^2^]. It does not have any lyrics, as far as I know. Maybe you are looking for another song?