Complex sentence: Pitt swam for the gold medal-winning U.S. team in the preliminary heats of the women's 4x100-meter medley relay, but was not eligible for a medal under the 1964 international swimming rules because she did not swim in the event final.
Split into simpler sentences: Pitt swam for the gold medal-winning U.S. team in the preliminary heats of the women's 4x100-meter medley relay. She was not eligible for a medal under the 1964 international swimming rules, however, because she did not swim in the event final.