Complex sentence: Liverpool dominated English football from 1975 to 1990, winning eleven league championships and four European Cups, including several seasons in which they won multiple trophies in both domestic and European competitions.
Split into simpler sentences: Liverpool dominated English football from 1975 to 1990, winning 11 league championships and four European Cups. During their respective periods of dominance, both teams enjoyed several seasons in which they won multiple trophies in both domestic and European competitions.