The German shepherd dog is chasing after a ball.
a dog chasing a ball.
A German shepherd dog is a kind of dog.
exists e1 s1 x1 x2 x3.(n_dog(x1) & of(x1,x2) & n_shepherd(x2) & a_german(s1) & Theme(s1,x1) & after(e1,x3) & n_ball(x3) & Actor(e1,x1) & v_chase(e1))
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_chase(e1) & n_ball(x3) & (x1 = x2) & n_dog(x1))