Complex sentence: In the Polish People's Republic, Lipiński was an influential Marxian economist and long-term communist party member; outspoken in his criticism of government policies, he eventually became active in opposition circles.
Split into simpler sentences: In the Polish People's Republic, Lipiński was an influential Marxian economist and a long-term member of the communist party. Outspoken in his criticism of government policies, he became active in opposition circles.