How Happy We Are This song is in three-quarter time. "How Happy We Are" is in the key of B-flat major in three-quarter time. "How Happy We Are" is a singing lesson in the seventh lesson of the fifth-grade primary school music volume in Huacheng Edition. The children's song "How Happy We Are" was composed by Zheng Lucheng and lyrics by Jin Fan. Beat and rhythm are one of the most important elements of music. Matter is in motion. As long as motion exists, rhythm will inevitably occur.