Complex sentence: She did not qualify for the semi-final in the 100m butterfly event, but qualified fastest for the final of the 200m Butterfly, and won silver, finishing just three-hundredths of a second behind Spain's Mireia Belmonte.
Split into simpler sentences: She did not qualify for the semi-final in the 100 m butterfly event, but qualified fastest for the final of the 200 m butterfly. She won silver, finishing just three-hundredths of a second behind Spain's Mireia Belmonte.