The Spirit showed Scrooge the time when he was alone at boarding school during the holidays as the first part of his past.
The first part of Scrooge’s past that the Spirit showed him in Charles Dickens' “A Christmas Carol” was his time as a young boy at boarding school, alone during the holiday season while other children went home to their families. This scene is significant as it marks the beginning of Scrooge's journey into understanding his life and the choices that have led him to become the person he is. The loneliness and isolation of his youth are depicted, highlighting the lack of warmth and family ties in his early life and setting the stage for his transformation.