Complex sentence: Sive graduated from Brooklyn College with a degree in political science in 1943, and enlisted in the U.S. Army in 1942 and was called up in the spring of 1943 shortly before his college graduation.
Split into simpler sentences: Sive graduated from Brooklyn College with a degree in political science in 1943. He had enlisted in the U.S. Army in 1942 and was called up in the spring of 1943 shortly before his college graduation.