Complex sentence: The 2008--09 Australian region cyclone season, a cycle of tropical cyclone formation, officially started on 1 November 2008 and ended on 30 April 2009.
Split into simpler sentences: The 2008--09 Australian region cyclone season was an event in the cycle of tropical cyclone formation. It officially started on 1 November 2008, and officially ended on 30 April 2009.