A guy is skateboarding of a metal staircase.
A guy skateboards.
When a guy is skateboarding up a metal staircase then the guy most certainly skateboards.
exists e1 x1 x2 x3.(of(e1,x2) & n_staircase(x2) & of(x2,x3) & n_metal(x3) & Actor(e1,x1) & v_skateboard(e1) & n_guy(x1))
exists x1 x2.(a_topic(x1) & Time(x1,x2) & n_skateboard(x2) & n_guy(x1))