Complex sentence: The 1980 U.S. Open was the 80th U.S. Open, held June 12--15 at Baltusrol Golf Club in Springfield, New Jersey.
Split into simpler sentences: The 1980 U.S. Open was the 80th U.S. Open. The golf tournament was held June 12--15,1980, at Baltusrol Golf Club in Springfield, New Jersey.