The dog has a ball in its mouth.
A dog is playing fetch.
A dog does not have to be playing fetch to have a ball in its mouth.
exists e1 x1 x2 x3.(n_mouth(x3) & of(x3,x1) & n_thing(x1) & n_dog(x1) & Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & in(x2,x3) & n_ball(x2))
exists e1 s1 x1.(a_fetch(s1) & Manner(e1,s1) & Actor(e1,x1) & v_play(e1) & n_dog(x1))