Dirt bikers on a trail.
humans outside
If you are on a trail you are outside
exists x1 x2 x3.(a_topic(x1) & on(x1,x3) & n_trail(x3) & n_biker(x1) & (x1 = x2) & ne_nam_dirt(x2))
exists s1 x1 x2.(a_topic(x1) & Theme(s1,x2) & a_outside(s1) & (x1 = x2) & n_human(x1))