People are walking down a street.
People are shopping in a busy city.
Walking does not imply shopping and not every busy street is in a city.
exists e1 x1 x2.(down(e1,x2) & n_street(x2) & Actor(e1,x1) & v_walk(e1) & n_people(x1))
exists e1 s1 x1 x2.(in(e1,x2) & n_city(x2) & a_busy(s1) & Theme(s1,x2) & Actor(e1,x1) & v_shop(e1) & n_people(x1))