two horses with riders, race along the track.
A horse race in progress.
To race along the track implies that the race is in progress.
exists x1 x2 x3 x4.(n_track(x4) & a_topic(x1) & with(x1,x2) & rel(x2,x3) & along(x3,x4) & n_race(x3) & n_rider(x2) & n_horse(x1) & card_eq_2(x1))
exists x1 x2 x3.(a_topic(x1) & in(x1,x3) & n_progress(x3) & n_race(x1) & of(x1,x2) & n_horse(x2))