Complex sentence: Born in Westcliff-on-Sea, Essex, England, Clement was educated at Bishop's Stortford College, he then spent a year in the United States on an exchange visit and upon his return he completed his National Service with the Royal Air Force.
Split into simpler sentences: Born in Westcliff-on-Sea, Essex, England, Clement was educated at Bishop's Stortford College, and then spent a year in the United States on an exchange visit. Upon his return, he completed his National Service with the Royal Air Force.