Complex sentence: On January 31,1943, William Simmons died of a stroke, and within a year Simmons's mother had remarried, this time to William D. Griffen, a civil engineer for the U.S. Army Corps of Engineers.
Split into simpler sentences: On January 31,1943, William Simmons died of a stroke. Within a year, Simmons's mother married again, this time to William D. Griffen, a civil engineer for the U.S. Army Corps of Engineers.