According to QQ music query, "through my happy past" is the lyrics in "Angel's Wings". Angel Wings Singing: Xu Yuteng, Album: Angel Wings, Language: Mandarin, Genre: Pop, Record Company: Fish, Water and Fish.
Part of the lyrics: Where will the fallen leaves go with the wind, leaving only a beautiful sky? The voice that used to dance in my happy past like the wings of an angel, the place where love has been, vaguely retains the fragrance of yesterday, and the warmth as familiar as the wings of an angel, which has crossed my endless thoughts. I believe you are still there and have never left.