Complex sentence: He spent 1944 to 1946 in the Army at Dugway Proving Ground in Utah, and then attended Harvard University, beginning in 1946 and graduating in the class of 1950, where he studied French and roomed with poet Frank O'Hara.
Split into simpler sentences: He spent 1944 to 1946 in the Army at Dugway Proving Ground in Utah. He then attended Harvard University, beginning in 1946 and graduating in the class of 1950; he studied French and roomed with poet Frank O'Hara.