For example, a man may choose to walk across a bridge or not to walk across it; what he may not choose is to fly over the bridge—his nature prevents him from flying.
Kwa mfano, mtu anaweza kuamua kutembea katika daraja au kutotembea juu yake, chenye anaweza kuamua kutofanya ni kuruka juu ya daraja hiyo- asili yake humzuia kuruka.