A black and white dog is running over grass.
A terrier runs to find his boy.
A black and white dog running over grass does not have to be a terrier and could have a purpose other than trying to find his boy.
exists e1 s1 s2 x1 x2.(over(e1,x2) & n_grass(x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1) & a_white(s2) & Theme(s2,x1) & a_black(s1) & Theme(s1,x1))
exists e1 p1 x1 x2 x3.(Topic(e1,p1) & exists e2.(Theme(e2,x3) & Actor(e2,x1) & v_find(e2)) & n_boy(x3) & of(x3,x1) & n_male(x1) & Actor(e1,x2) & v_run(e1) & n_terrier(x2) & n_terrier(x1))