A woman whose head is not visible walks in front of a bus with an advertisement on its side.
The womans head is visible
The woman's head cannot be visible if it is not visible.
exists e1 x1 x2 x3 x4 x5 x6.(in(e1,x3) & of(x3,x4) & with(x4,x5) & on(x5,x6) & n_side(x6) & of(x6,x1) & n_thing(x1) & n_advertisement(x5) & n_bus(x4) & n_front(x3) & Actor(e1,x1) & v_walk(e1) & -exists s1.(Theme(s1,x2) & a_visible(s1)) & n_head(x2) & of(x2,x1) & n_woman(x1))
exists s1 x1 x2.(n_head(x1) & of(x1,x2) & n_woman(x2) & Theme(s1,x1) & a_visible(s1))