On garden lawn, black dog is retriving an object.
The dog is playing fetch with his owner.
Just because it is  On garden lawn, black dog is retriving an object does not mean it is with its owner.
exists e1 s1 x1 x2 x3 x4.(on(e1,x3) & n_lawn(x3) & of(x3,x4) & n_garden(x4) & Theme(e1,x2) & Actor(e1,x1) & v_retrive(e1) & n_object(x2) & n_dog(x1) & a_black(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(n_owner(x3) & of(x3,x1) & n_male(x1) & n_dog(x1) & with(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_fetch(x2))