Boy skating across a metal rail.
The boy is performing in front of others.
Others may not be there.
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 x3.(n_boy(x1) & in(e1,x2) & of(x2,x3) & -(x3 = x2) & n_person(x2) & n_person(x3) & n_front(x2) & Actor(e1,x1) & v_perform(e1))