A family sits for a picture on a staircase outside.
People are playing fetch with their dog.
People cannot be  sit and playing simultaneously.
exists e1 x1 x2 x3 x4.(on(e1,x3) & n_outside(x3) & of(x3,x4) & n_staircase(x4) & for(e1,x2) & n_picture(x2) & Actor(e1,x1) & v_sit(e1) & n_family(x1))
exists e1 x1 x2 x3.(with(e1,x3) & n_dog(x3) & of(x3,x1) & n_thing(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_fetch(x2) & n_people(x1))