Complex sentence: His father was Oklahoma Supreme Court Justice Marian P. Opala (1921-2010), who fought in the Polish Underground during World War II before immigrating to the U.S. in 1947.
Split into simpler sentences: His father was Marian P. Opala (1921-2010), who became an Oklahoma Supreme Court Justice. He had fought in the Polish Underground during World War II and immigrated to the U.S. in 1947.