A man with a backpack is observing an alligator.
The man is being eaten by an alligator
The man cannot be observing the alligator if he is being eaten by the alligator.
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_observe(e1) & n_alligator(x3) & with(x1,x2) & n_backpack(x2) & n_man(x1))
exists e1 x1 x2.(n_man(x1) & Actor(e1,x2) & n_alligator(x2) & Theme(e1,x1) & v_eat(e1))