Complex sentence: He graduated with a BS in Industrial Mangement from the University of Ilinois and, during World War 2, served as a colonel of guerrillas in the Bulacan area, where he fought against the Japanese.
Split into simpler sentences: He graduated with a BS in Industrial Mangement from the University of Illinois. During World War 2 Fabian served as a colonel of guerrillas in the Bulacan area, where he fought against the Japanese.