Rollerblades sliding on a railing.
Rollerblades are sliding on a railing during a trick.
Not all rollerblades are a trick.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_railing(x3) & Actor(e1,x2) & v_slide(e1) & (x1 = x2) & n_rollerblade(x1))
exists e1 x1 x2 x3.(during(e1,x3) & n_trick(x3) & on(e1,x2) & n_railing(x2) & Actor(e1,x1) & v_slide(e1) & n_rollerblade(x1))