1, "spirit": people are not poor in ambition, stick to a simple life and simple emotions. "Lesson": People are changeable and unpredictable, especially in this materialized society, and sincere help cannot be really understood.

2. No reason: ① "a pottery bowl" runs through the novel as a clue, and the plot of the novel revolves around it; ② A Pottery Bowl, as the title, has implicit meaning and can arouse readers' interest; 3 "transformation" is too straightforward and not implicit enough.

3. Omission