Three men are working on scaffolding on the side of a building.
Three construction workers install scaffolding on a building.
If men are working on scaffolding, then they are construction workers.  If men install scaffolding, then they are working on the scaffolding.
exists e1 e2 x1 x2 x3 x4.(n_side(x3) & on(e1,e2) & on(e2,x3) & of(x3,x4) & n_building(x4) & Actor(e2,x2) & v_scaffold(e2) & Actor(e1,x1) & v_work(e1) & n_man(x1) & card_eq_3(x1))
exists e1 p1 x1 x2.(exists e2 x3.(on(e2,x3) & n_building(x3) & Actor(e2,x1) & v_scaffold(e2)) & Topic(e1,p1) & Actor(e1,x1) & v_install(e1) & n_worker(x1) & of(x1,x2) & n_construction(x2) & card_eq_3(x1))