Complex sentence: Dennis O'Neil denies the Knightfall storyline was in any way inspired by the Death of Superman and states that it was already in development by as much as three years, saying that if the Batman staff known, the storyline would likely have been pushed down a year.
Split into simpler sentences: Dennis O'Neil denies the Knightfall storyline was in any way inspired by the Death of Superman and that it was already in development by as much as three years. Had the Batman staff known, the storyline would likely have been pushed down a year.