The girl is on a swing.
A tire is swingingon the girl.
if the girl is swinging on the tire, the tire cannot swing on the girl.
exists p1 x1.(n_girl(x1) & exists x2.(on(x1,x2) & n_swing(x2)))
exists e1 x1 x2.(n_girl(x2) & Recipient(e1,x2) & Theme(e1,x1) & v_swingingon(e1) & n_tire(x1))