Complex sentence: Melkert attended a Roman-Catholic primary school in Moordrecht until 1968, after which he continued his studies at the Coornhert Gymnasium in Gouda, a state school specialising in the arts.
Split into simpler sentences: Melkert attended a Roman-Catholic primary school in Moordrecht until 1968. He continued to study at the public Coornhert Gymnasium in Gouda, specialising in the arts.