Complex sentence: Duncan John D'Arcy Armstrong, OAM, (born 7 April 1968 in Rockhampton, Queensland) is an Australian freestyle swimmer of the 1980s, who won gold in the 200 m freestyle at the 1988 Seoul Olympics.
Split into simpler sentences: Duncan John D'Arcy Armstrong, OAM, (born 7 April 1968) is a former Australian swimmer and Olympic gold medalist. Amrmstrong freestyle swimmer of the 1980s, who won gold in the 200 m freestyle at the 1988 Seoul Olympics.