A rider on a dirt bike races through a forest.
The skateboard is racing through the forest.
A skateboard and a dirt bike are different vehicles.
exists x1 x2 x3 x4 x5.(a_topic(x1) & through(x1,x5) & n_forest(x5) & on(x1,x2) & n_race(x2) & of(x2,x4) & n_bike(x4) & of(x2,x3) & n_dirt(x3) & n_rider(x1))
exists e1 x1 x2.(n_forest(x2) & n_skateboard(x1) & through(e1,x2) & Actor(e1,x1) & v_race(e1))