Complex sentence: In April 1915, Obregón scored a decisive victory over Villa in the Bajío at the Battle of Celaya, which saw 4,000 of Villa's soldiers killed and another 6,000 captured, and in May 1915, González began a campaign against the last-remaining Zapatistas.
Split into simpler sentences: In April 1915, Obregón scored a decisive victory over Villa in the Bajío at the Battle of Celaya, in which 4,000 of Villa's soldiers were killed and another 6,000 captured. In May 1915, González began a campaign against the last-remaining Zapatistas.