A dog in a field.
A dog is swimming at the beach.
If a dog is swimming at the beach, he or she is not in a field.
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_field(x2) & n_dog(x1))
exists e1 x1 x2.(n_beach(x2) & at(e1,x2) & Actor(e1,x1) & v_swim(e1) & n_dog(x1))