A black and brown dog is running with a tennis ball in its mouth.
A dog playing fetch.
The dog running with a tennis ball in its mouth is not necessarily playing fetch.
exists e1 s1 s2 x1 x2 x3 x4.(in(e1,x4) & n_mouth(x4) & of(x4,x1) & n_thing(x1) & with(e1,x2) & n_ball(x2) & of(x2,x3) & n_tennis(x3) & Actor(e1,x1) & v_run(e1) & n_dog(x1) & a_brown(s2) & Theme(s2,x1) & a_black(s1) & Theme(s1,x1))
exists e1 x1 x2.(Actor(e1,x1) & v_fetch(e1) & n_playing(x1) & of(x1,x2) & n_dog(x2))