A dog with something pink in its mouth is looking forward.
There is nothing in the animal's mouth.
If there is nothing in the animal's mouth then it cannot have something pink in its mouth.
exists e1 p1 x1 x2 x3 x4.(exists s1.(Theme(s1,x1) & a_forward(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_look(e1) & with(x1,x2) & in(x2,x4) & n_mouth(x4) & of(x4,x1) & n_thing(x1) & Time(x2,x3) & n_pink(x3) & n_thing(x2) & n_dog(x1))
exists p1 x1 x3 x4.(n_mouth(x4) & of(x4,x3) & n_animal(x3) & -exists x2.((x1 = x2) & in(x2,x4) & n_thing(x2)))