Complex sentence: The 1986 U.S. Open was the 86th U.S. Open, held June 12--15 at Shinnecock Hills Golf Club in Shinnecock Hills, New York.
Split into simpler sentences: The 1986 U.S. Open was the 86th U.S. Open. The golf tournament was held June 12--15,1986, at Shinnecock Hills Golf Club in Shinnecock Hills, New York.