Complex sentence: The 1971 U.S. Open was the 71st U.S. Open, held June 17--21 at the East Course of Merion Golf Club in Ardmore, Pennsylvania, a suburb northwest of Philadelphia.
Split into simpler sentences: The 1971 U.S. Open was the 71st U.S. Open. The golf tournament was held June 17--21,1971, at the East Course of Merion Golf Club in Ardmore, Pennsylvania, a suburb northwest of Philadelphia.