Final answer:
Annie and Millie's friendship likely grew from their shared interest in religion and the spiritual goals they pursued, as well as Annie's support of Millie's marriage to Frank Erne.
Step-by-step explanation:
The question appears to be related to character relationships in literary texts, specifically how and why certain characters, like Annie and Millie, became friends. Friendships in literature often evolve through shared experiences, common values, or emotional connections.
For Annie and Millie, their bond might have grown from their mutual interest in religion and the desire to pursue spiritual goals, as evident through their dedication to church activities and Bible study.
Additionally, Annie's acceptance and support of Millie's marriage to Frank Erne, a character with whom Annie also formed a deep friendship, likely solidified their comradery. Character development and the complexity of human relationships are central themes in such narratives.
The exploration of these dynamics allows readers to connect with the characters on a personal level, understanding the intricate web of interactions that influence their actions and emotions.