Why do you think Sachar (the author) alternates between the past and the present throughout the story?

Sachar alternates between the past and the present to create a deeper understanding of the characters' motivations and experiences. This technique allows readers to see how past events shape the characters' current lives, highlighting themes of fate, friendship, and resilience. By juxtaposing different timelines, he builds suspense and reveals the interconnectedness of their stories, enriching the narrative's emotional impact. Ultimately, this structure enhances the exploration of how history influences identity and choices.