Two people walking down an alley.
There are two people in the back street.
Backstreet  is another way to say alley.
exists e1 s1 x1 x2 x3.(a_topic(x1) & a_down(s1) & Manner(e1,s1) & Theme(e1,x3) & Actor(e1,x2) & v_walk(e1) & n_alley(x3) & (x1 = x2) & n_people(x1) & card_eq_2(x1))
exists p1 s1 x1 x3.(n_street(x3) & a_back(s1) & Theme(s1,x3) & exists x2.((x1 = x2) & in(x2,x3) & n_people(x2) & card_eq_2(x2)))