A man sits on the gravel by an ocean.
A man running along the beach.
You can't sit and be running at the same time.
exists e1 x1 x2 x3.(n_gravel(x2) & by(e1,x3) & n_ocean(x3) & on(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists e1 x1 x2 x3.(n_beach(x3) & a_topic(x1) & along(e1,x3) & Actor(e1,x2) & v_run(e1) & (x1 = x2) & n_man(x1))