Original sentence: Maria Koszutska (pseudonim Wera Kostrzewa) (1876-1939) was a leader and theoretician of the Polish Socialist Party "Left" faction (Polska Partia Socialistyczna, PPS  — Lewica) and later of the Communist Party of Poland (KPP).With interruptions, she sat on the Central Committee of the KPP 1918-29 and its politburo 1923-29
Edited sentence: Maria Koszutska (pseudonym Wera Kostrzewa) (1876-1939) was a leader and theoretician of the Polish Socialist Party "Left" faction (Polska Partia Socialistyczna, PPS  — Lewica) and later of the Communist Party of Poland (KPP).With interruptions, she sat on the Central Committee of the KPP 1918–29 and its politburo 1923-29