Complex sentence: In 1989, Jurgens began working full-time on the character when he took over the writing/pencilling of the monthly "The Adventures of Superman" and had a run as artist of "Green Arrow" with writer Mike Grell from 1988-1990.
Split into simpler sentences: In 1989, Jurgens began working full-time on the character when he took over the writing/pencilling of the monthly "The Adventures of Superman". He also had a run as artist of "Green Arrow" with writer Mike Grell from 1988-1990.