Complex sentence: Alec and Janet's mischievous, troublesome older son, he befriends Izzy (Isolde), daughter of Mr. Pettibone, the widower schoolteacher who takes over after Hetty retires.
Split into simpler sentences: Alec and Janet's mischievous, troublesome older son. He befriends Izzy (Isolde), daughter of Mr. Pettibone, the widower schoolteacher who takes over after Hetty retires.