Man are standing on scaffolding and working on a building.
Men are on a scaffold.
A scaffold is used to work on a building.
exists e1 e2 x1 x2 x3 x4.(on(e2,x4) & n_building(x4) & Actor(e2,x3) & v_work(e2) & n_man(x3) & on(e1,x2) & n_scaffolding(x2) & Actor(e1,x1) & v_stand(e1) & n_man(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_scaffold(x2)) & n_man(x1))