A boy on a swing.
A boy swinging on a tire swing.
Sentence 1 is missing swinging on a tire swing
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_swing(x2) & n_boy(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & on(e1,x3) & n_swing(x3) & of(x3,x4) & n_tire(x4) & Actor(e1,x2) & v_swing(e1) & (x1 = x2) & n_boy(x1))