Chairs have been placed in front of a building.
Chairs in front of a building.
In a both sentence, Chairs in front of building.
exists e1 x1 x2 x3.(in(e1,x2) & of(x2,x3) & n_building(x3) & n_front(x2) & Theme(e1,x1) & v_place(e1) & n_chair(x1))
exists x1 x2 x3.(a_topic(x1) & in(x1,x2) & of(x2,x3) & n_building(x3) & n_front(x2) & n_chair(x1))