A woman is standing front of a sign.
There is a sign behind the woman.
If the woman is standing in front of a sign, then the sign must be behind her.
exists p1 x1.(exists e1 x2 x3.((x1 = x2) & of(x2,x3) & n_sign(x3) & n_front(x2) & Actor(e1,x2) & v_stand(e1)) & n_woman(x1))
exists p1 x1 x3.(n_woman(x3) & exists x2.((x1 = x2) & behind(x2,x3) & n_sign(x2)))