Complex sentence: Lennon attended St. James the Apostle grammar school in St. James parish in Arlington, where he was an altar boy and graduated in 1965 from Matignon, a Catholic High School in Cambridge, Mass., where he was a member of the National Honor Society.
Split into simpler sentences: Lennon attended St. James the Apostle grammar school in St. James parish in Arlington, where he was an altar boy. In 1965 Lennon graduated from Matignon, a Catholic High School in Cambridge, Mass., where he was a member of the National Honor Society.