A security guard standing alone by a building wall.
A woman is guarding the building.
The security guard mentioned might not be a woman.
exists x1 x2 x3 x4 x5.(a_topic(x1) & by(x1,x4) & n_wall(x4) & of(x4,x5) & n_building(x5) & r_alone(x1) & n_standing(x1) & of(x1,x3) & n_guard(x3) & of(x1,x2) & n_security(x2))
exists e1 x1 x2.(n_building(x2) & Theme(e1,x2) & Actor(e1,x1) & v_guard(e1) & n_woman(x1))