Complex sentence: The U.S. did not win the most gold medals for the first time in a Summer Games since 1992, losing to China (48--36), and United States never led the medal table during the games.
Split into simpler sentences: The U.S. did not win the most gold medals for the first time in a Summer Games since 1992, with China being the country that won the most medals (48--36). The United States never led the medal table during the games.