Complex sentence: After weeks of consideration, Jimmie now Jim decided to simply drop his last name and go by James Gordon which is how he enrolled in eighth grade and the name he used throughout high school and his first year and a half of university.
Split into simpler sentences: After weeks of consideration, Jimmie now Jim decided to simply drop his last name and go by James Gordon--which is how he enrolled in eighth grade. He used the name throughout high school and his first year and a half of university.