Complex sentence: Paletta returned to Argentina after one year with Liverpool to join Boca Juniors, he played in the 2007 FIFA Club World Cup Final in which Boca Juniors lost 4--2 against AC Milan.
Split into simpler sentences: Paletta returned to Argentina after one year with Liverpool to join Boca Juniors. Paletta played in the 2007 FIFA Club World Cup Final in which Boca Juniors lost 4--2 against AC Milan.