A boy swings on a swing set.
A boy is making a sand castle.
A boy who swings on a swing set can't also be making a sand castle.
exists x1 x2 x3 x4.(a_topic(x1) & on(x1,x3) & n_set(x3) & of(x3,x4) & n_swing(x4) & n_swing(x1) & of(x1,x2) & n_boy(x2))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_make(e1) & n_castle(x2) & of(x2,x3) & n_sand(x3) & n_boy(x1))