Two boys waterskiing.
boys race on waterskies
Boys waterskiing does not mean they are in a race.
exists e1 x1.(Actor(e1,x1) & v_waterskie(e1) & n_boy(x1) & card_eq_2(x1))
exists x1 x2 x3.(a_topic(x1) & on(x1,x3) & n_watersky(x3) & n_race(x1) & of(x1,x2) & n_boy(x2))