A boy walks near buildings.
A boy is walking near some structures.
Buildings are structures.
exists e1 x1 x2.(near(e1,x2) & n_building(x2) & Actor(e1,x1) & v_walk(e1) & n_boy(x1))
exists e1 x1 x2.(near(e1,x2) & n_structure(x2) & Actor(e1,x1) & v_walk(e1) & n_boy(x1))