Complex sentence: Worldcon committees may also give out special awards during the Hugo ceremony, which are not voted on; unlike the additional Hugo categories which Worldcons may present, these awards are not officially Hugo Awards and do not use the same trophy, though they once did.
Split into simpler sentences: Worldcon committees may also give out special awards during the Hugo ceremony, which are not voted on. Unlike the additional Hugo categories which Worldcons may present, these awards are not officially Hugo Awards and do not use the same trophy, though they once did.