A skier speeds through the snow.
A skier races through a competition.
The second sentence states the skier is in a competition and not just skiing for recreation
exists e1 x1 x2.(n_snow(x2) & through(e1,x2) & Actor(e1,x1) & v_speed(e1) & n_skier(x1))
exists x1 x2 x3.(a_topic(x1) & through(x1,x3) & n_competition(x3) & n_race(x1) & of(x1,x2) & n_skier(x2))