A brown dog is fetching something in its mouth on a field.
The brown dog fetched a baseball
A brown dog fetching something is not necessarily a baseball.
exists e1 s1 x1 x2 x3 x4.(Theme(e1,x2) & Actor(e1,x1) & v_fetch(e1) & in(x2,x3) & on(x3,x4) & n_field(x4) & n_mouth(x3) & of(x3,x1) & n_thing(x1) & n_thing(x2) & n_dog(x1) & a_brown(s1) & Theme(s1,x1))
exists e1 s1 x1 x2.(n_dog(x1) & a_brown(s1) & Theme(s1,x1) & Theme(e1,x2) & Actor(e1,x1) & v_fetch(e1) & n_baseball(x2))