Complex sentence: Over the past 15 years CEHS has won many titles in the state of Maine, teams from all sports in which students currently participate have won at least one state championship except downhill skiing and girls' lacrosse.
Split into simpler sentences: Over the past 15 years CEHS has won many titles in the state of Maine. Teams from all sports in which students currently participate have won at least one state championship except downhill skiing and girls' lacrosse.