Complex sentence: At the 1991 World Aquatics Championships in Perth, Western Australia, Haislett won the 100-meter and 400-meter freestyle and medley relays, ending the East German women's eighteen years of overwhelming dominance in the 100-meter freestyle at the World Championships.
Split into simpler sentences: At the 1991 World Aquatics Championships in Perth, Western Australia, Haislett won the 100-meter and 400-meter freestyle and medley relays. She also ended the eighteen-year East German reign in the 100-meter freestyle at the World Championships.