Construction worker doing his job on scaffolding.
A laborer performs work on a structure.
A laborer may be a construction worker, doing his job in scaffolding work on a structure means the same.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & Theme(e1,x4) & Actor(e1,x3) & v_do(e1) & on(x4,x5) & n_scaffolding(x5) & n_job(x4) & of(x4,x1) & n_male(x1) & (x1 = x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & on(x2,x3) & n_structure(x3) & n_work(x2) & n_laborer(x1))