A man sleeps while listening to his iPod in the back of a vehicle.
Someone listening to audio.
If he is listening to his iPod, then he is listening to audio.
exists e2 e1 x1 x2 x3 x4.(n_back(x3) & while(e1,e2) & to(e2,x2) & in(x2,x3) & of(x3,x4) & n_vehicle(x4) & n_ipod(x2) & of(x2,x1) & n_male(x1) & Actor(e2,x1) & v_listen(e2) & Actor(e1,x1) & v_sleep(e1) & n_man(x1))
exists x1 x2.(a_topic(x1) & to(x1,x2) & n_audio(x2) & n_listening(x1))