Two men digging at a construction sight.
Two men digging to check for gas lines.
Two men may dig at a construction site for many reasons, not only to check for gas lines
exists e1 x1 x2 x3 x4.(a_topic(x1) & at(e1,x3) & n_sight(x3) & of(x3,x4) & n_construction(x4) & Actor(e1,x2) & v_dig(e1) & (x1 = x2) & n_man(x1) & card_eq_2(x1))
exists e1 p1 x1 x2.(a_topic(x1) & Topic(e1,p1) & Actor(e1,x2) & v_dig(e1) & exists e2 x3 x4.(for(e2,x3) & n_line(x3) & of(x3,x4) & n_gas(x4) & Actor(e2,x2) & v_check(e2)) & (x1 = x2) & n_man(x1) & card_eq_2(x1))