A child swinging on a swing-set.
A child on a swing is being pushed by a man.
Not every child on a swing set is being pushed by a man.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_swing-set(x3) & Actor(e1,x2) & v_swing(e1) & (x1 = x2) & n_child(x1))
exists e1 x1 x2 x3.(Actor(e1,x3) & n_man(x3) & Theme(e1,x1) & v_push(e1) & on(x1,x2) & n_swing(x2) & n_child(x1))