A boy skateboards down the metal handrail at night.
The boy is on a skateboard.
A boy on a skateboard is slippery at night.
exists e1 x1 x2 x3 x4.(n_handrail(x2) & of(x2,x3) & n_metal(x3) & at(e1,x4) & n_night(x4) & down(e1,x2) & Actor(e1,x1) & v_skateboard(e1) & n_boy(x1))
exists p1 x1.(n_boy(x1) & exists x2.(on(x1,x2) & n_skateboard(x2)))