A man using a scaffold to work on the roof of a building.
A person is working.
If a man is using a scaffold to work then a person is working.
exists e1 p1 x1 x2 x3 x4.(n_roof(x4) & a_topic(x1) & Theme(e1,p1) & Recipient(e1,x3) & Actor(e1,x2) & v_use(e1) & exists e2 x5.(on(e2,x4) & of(x4,x5) & n_building(x5) & Actor(e2,x2) & v_work(e2)) & n_scaffold(x3) & (x1 = x2) & n_man(x1))
exists e1 x1.(Actor(e1,x1) & v_work(e1) & n_person(x1))