people are walking down an alley.
The people are walking.
Both subjects are walking
exists e1 s1 x1 x2.(a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_alley(x2) & n_people(x1))
exists e1 x1.(n_people(x1) & Actor(e1,x1) & v_walk(e1))