A white dog drinks water on a mountain.
A dog drinks water from a mountain stream.
Just because it is a mountain doesn't mean it is a mountain stream.
exists s1 x1 x2 x3 x4.(a_topic(x1) & on(x1,x4) & n_mountain(x4) & n_water(x1) & of(x1,x3) & n_drink(x3) & of(x1,x2) & n_dog(x2) & a_white(s1) & Theme(s1,x1))
exists x1 x2 x3 x4 x5.(a_topic(x1) & from(x1,x4) & n_stream(x4) & of(x4,x5) & n_mountain(x5) & n_water(x1) & of(x1,x3) & n_drink(x3) & of(x1,x2) & n_dog(x2))