Two motocross bikes are being raced around a dirt track.
Two bikers race.
Bikes cannot race without bikers, so two bikes in a race implies two bikers riding them.
exists e1 x1 x2 x3 x4.(around(e1,x3) & n_track(x3) & of(x3,x4) & n_dirt(x4) & Theme(e1,x1) & v_race(e1) & n_bike(x1) & of(x1,x2) & n_motocross(x2) & card_eq_2(x1))
exists s1 x1 x2.(n_race(x1) & a_.(s1) & Theme(s1,x1) & of(x1,x2) & n_biker(x2) & card_eq_2(x1) & a_topic(x1))