Complex sentence: In the 2006-2007 season, Moon entered the WPIAL Class AAAA, but will go back down to WPIAL Class AAA in the 2008-2009 season.
Split into simpler sentences: In the 2006-2007 season, Moon entered the WPIAL Class AAAA. But will go back down it WPIAL Class AAA in the 2008-2009 season.