The snow borader is riding a rail.
a person is doing tricks.
The snow boarder is a person. Riding a rail is doing a trick.
exists e1 x1 x2 x3.(n_borader(x1) & of(x1,x2) & n_snow(x2) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_rail(x3))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & n_person(x1))