Complex sentence: Bellmon agreed to run, and in November, Oklahoma voters returned Bellmon to the Governor's Mansion for a second term and he served from January 12,1987 to January 14,1991.
Split into simpler sentences: Bellmon agreed to run, and in November, Oklahoma voters elected Bellmon governor of Oklahoma for a second term. He served from January 12,1987 to January 14,1991.