Complex sentence: The 1919 U.S. Open was the 23rd U.S. Open, held June 9--12 at Brae Burn Country Club in West Newton, Massachusetts.
Split into simpler sentences: The 1919 U.S. Open was the 23rd U.S. Open. The golf tournament was held June 9--12,1919, at Brae Burn Country Club in West Newton, Massachusetts.