Complex sentence: He joined the Green Party in 1988 and was co-opted to Dublin City Council in 1998 and in 1999 he topped the poll in the local elections for the Rathmines area.
Split into simpler sentences: He joined the Green Party in 1988 and was co-opted to Dublin City Council in 1998. In 1999 he topped the poll in the local elections for the Rathmines area.