And now for a few with the -es ending in which that word could be either the one who sees or the one who is seen. Sample: Naves vidérunt Románi. The answer is: naves, because Románi could only be the ones who see, not the ones who are seen, and so naves must be the ones who are seen.
Mark the things that are had or seen:
Naves vidérunt Románi. Naves Románi habuérunt. Habuérunt naves Romános. Romános naves habuérunt. Romános urbes habuérunt.