A dog on a leash walks on the sidewalk while another dog follows.
A dog follows another dog.
in a both sentence leash and follows is different
exists e1 p1 x1 x2 x3.(n_sidewalk(x3) & exists e2 x4.(Actor(e2,x4) & v_follow(e2) & n_dog(x4) & -(x4 = x1)) & n_dog(x1) & n_dog(x1) & while(e1,p1) & on(e1,x3) & Actor(e1,x1) & v_walk(e1) & on(x1,x2) & n_leash(x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_follow(e1) & n_dog(x2) & -(x2 = x1) & n_dog(x1) & n_dog(x1))