Complex sentence: She writes letters to her mysterious benefactor regularly, but he never writes back; all she really knows about him is that she once saw his elongated shadow, hence her nickname for him, "Daddy Long Legs".
Split into simpler sentences: She writes letters to her mysterious benefactor regularly, but he never writes back. All she really knows about him is that she once saw his elongated shadow, hence her nickname for him, "Daddy Long Legs".