Complex sentence: Late one night, Edwina witnesses John's having sex with Carol in her bedroom and, in a jealous rage, beats him with a candlestick, causing him to fall down the grand staircase and break his leg.
Split into simpler sentences: Late one night, Edwina discovers John having sex with Carol in her bedroom. In a jealous rage, she beats him with a candlestick, causing him to fall down the staircase and break his leg.