A skateboarder sliding on a rail.
A boy wearing a tuxedo.
Skateboarder wouldn't be wearing a tuxedo.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_rail(x3) & Actor(e1,x2) & v_slide(e1) & (x1 = x2) & n_skateboarder(x1))
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_tuxedo(x3) & (x1 = x2) & n_boy(x1))