A light brown dog is chasing after a ball.
There is a dog chasing a ball.
A dog is chasing a ball, so it must be the light brown dog.
exists e1 s1 s2 x1 x2.(after(e1,x2) & n_ball(x2) & Actor(e1,x1) & v_chase(e1) & n_dog(x1) & a_brown(s2) & Theme(s2,x1) & a_light(s1) & Theme(s1,x1))
exists p1 x1 e1 x2 x3 x4.((x1 = x2) & Theme(e1,x4) & Actor(e1,x3) & v_chase(e1) & n_ball(x4) & (x2 = x3) & n_dog(x2))