Complex sentence: Kate (Lethbridge -) Stewart originated in the Reeltime film, "Downtime", Brigadier Lethbridge-Stewart having never mentioned a daughter on "Doctor Who"; she was canonised in "The Power of Three".
Split into simpler sentences: Kate (Lethbridge -) Stewart originated in the Reeltime film, "Downtime", Brigadier Lethbridge-Stewart having never mentioned a daughter on "Doctor Who". She was canonised in "The Power of Three".