A dog walks on the beach.
A dog runs through the snow.
A dog that walks on the beach cannot run through the snow same time.
exists e1 x1 x2.(n_beach(x2) & on(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_dog(x1))
exists e1 x1 x2.(n_snow(x2) & through(e1,x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1))