Complex sentence: Sauron also gave seven Rings of Power to the Dwarves, and Celebrimbor forged three, untainted by Sauron's evil, for the Elves.
Split into simpler sentences: Sauron also gave seven Rings of Power to the Dwarves. These were in addition to the three Celebrimbor forged, untainted by Sauron's evil, for the Elves.