Complex sentence: He was a U.S. Marine doing helicopter maintenance during the Lebanon crisis of 1958, attended New York University for a brief period and in 1959 went to Japan to assist in rural development and teach English.
Split into simpler sentences: He was a U.S. Marine doing helicopter maintenance during the Lebanon crisis of 1958, attended New York University for a brief period. In 1959 went to Japan to assist in rural development and teach English.