This is a grassy and rocky place.
This is a field.
just because it is a rocky place doesn't mean it is a field.
exists p1 x1.(n_thing(x1) & exists s1 x2 x3 x4.((x1 = x2) & subset_of(x4,x2) & n_place(x4) & a_rocky(s1) & Theme(s1,x4) & subset_of(x3,x2) & n_grassy(x3)))
exists p1 x1.(n_thing(x1) & exists x2.((x1 = x2) & n_field(x2)))