A boy sleeps on a car ride.
A boy is drooling while asleep.
A boy may not be drooling when he sleeps.
exists e1 x1 x2 x3.(on(e1,x2) & n_ride(x2) & of(x2,x3) & n_car(x3) & Actor(e1,x1) & v_sleep(e1) & n_boy(x1))
exists e1 x1 x2.(while(e1,x2) & n_asleep(x2) & Actor(e1,x1) & v_drool(e1) & n_boy(x1))