Complex sentence: He was a founder of the Workers' Party in February 1980 and vice-chairman of the party between 1991 and 1999, then state senator from São Paulo between 2003 and 2010.
Split into simpler sentences: He was a founder of the Workers' Party in February 1980 and vice chairman of the party between 1991 and 1999. Was state senator from São Paulo between 2003 and 2010.