Many people are walking along a street.
They are selling stuff.
People walking on the street are not necessarily selling stuff.
exists e1 x1 x2.(along(e1,x2) & n_street(x2) & Actor(e1,x1) & v_walk(e1) & n_people(x1) & n_quantity(x1))
exists e1 x1 x2.(n_thing(x1) & Theme(e1,x2) & Actor(e1,x1) & v_sell(e1) & n_stuff(x2))