A dog walks along a beach.
A dog is walking down a mountain.
A dog cannot be walking along a beach and walking down a mountain at the same time.
exists e1 x1 x2.(along(e1,x2) & n_beach(x2) & Actor(e1,x1) & v_walk(e1) & n_dog(x1))
exists e1 s1 x1 x2.(a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_mountain(x2) & n_dog(x1))