The black dog in the field has something in its mouth.
The dog a bird in it's mouth.
Not everything that a dog might have in its mouth is a bird.
exists e1 s1 x1 x2 x3 x4.(n_mouth(x4) & of(x4,x1) & n_thing(x1) & n_field(x2) & n_dog(x1) & a_black(s1) & Theme(s1,x1) & Theme(e1,x3) & Actor(e1,x1) & v_have(e1) & in(x3,x4) & n_thing(x3) & in(x1,x2))
exists x2.(n_dog(x2) & all x1.((n_thing(x1) & n_bird(x1)) -> exists p1.(exists x3.((x2 = x3) & n_mouth(x3)) & in(x2,x1) & for(x2,x1))))