Complex sentence: In spite of opposition, science fiction in comics continued through the 1960s with stories for children and adolescents and began to return to the adult market again in the late 60s with the wave of hippy underground comics.
Split into simpler sentences: In spite of opposition, science fiction in comics continued through the 1960s with stories for children and adolescents. It began to return to the adult market again in the late 60s with the wave of hippy underground comics.