Complex sentence: In 2007 GMC introduced the Acadia, a crossover SUV, which was the division's first unibody vehicle whose predecessor, the GMT-360 based Envoy, was discontinued with the closure of GM's Moraine, Ohio plant on December 23,2008.
Split into simpler sentences: In 2007 GMC introduced the Acadia, a crossover SUV, which was the division's first unibody vehicle. Its predecessor, the GMT-360 based Envoy, was discontinued with the closure of GM's Moraine, Ohio plant on December 23,2008.