Complex sentence: Penelope Corrin was her fill-in on "Air Farce" during Jessica's maternity leave during the first two months of 2007 and returned to the show in March 2007.
Split into simpler sentences: Penelope Corrin was her fill-in on "Air Farce" during Jessica's maternity leave during the first two months of 2007. She returned to the show in March 2007.