A skateboarder leaps in the air on a city street.
A skateboarder sits on the sidewalk.
The skateboarder cannot sits & leaps at the same time.
exists e1 x1 x2 x3 x4.(n_air(x2) & in(e1,x2) & on(x2,x3) & n_street(x3) & of(x3,x4) & n_city(x4) & Actor(e1,x1) & v_leap(e1) & n_skateboarder(x1))
exists e1 x1 x2.(n_sidewalk(x2) & on(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_skateboarder(x1))