Boy skating across a metal rail.
The boy is riding his tricycle.
Skating and riding are different.
exists e1 x1 x2 x3.(ne_nam_boy(x1) & across(e1,x2) & n_rail(x2) & of(x2,x3) & n_metal(x3) & Actor(e1,x1) & v_skate(e1))
exists e1 x1 x2.(n_tricycle(x2) & of(x2,x1) & n_male(x1) & n_boy(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1))