A man sleeps while listening to his iPod in the back of a vehicle.
A man sleeping while driving a car.
Person sleeping can not be listening at the same time.
exists e1 e2 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 e1 e2 x1 x2 x3.(a_topic(x1) & while(e1,e2) & Theme(e2,x3) & Actor(e2,x2) & v_drive(e2) & n_car(x3) & Actor(e1,x2) & v_sleep(e1) & (x1 = x2) & n_man(x1))