Complex sentence: In 1989 she was third at the U.S. Championships, but her big breakthrough came in 1991, when she won the U.S. Figure Skating Championships and placed second in the World Championships.
Split into simpler sentences: In 1989 she was third at the US Championships, but her big breakthrough was in 1991. In 1991 Harding won the U.S. Figure Skating Championships and placed second in the World Championships.