Young people talking in an alley.
Young people are in a gang.
Young people talking in an alley need not be in a gang.
exists e1 s1 x1 x2 x3.(a_topic(x1) & in(e1,x3) & n_alley(x3) & Actor(e1,x2) & v_talk(e1) & (x1 = x2) & n_people(x1) & a_young(s1) & Theme(s1,x1))
exists p1 s1 x1.(exists x2.(in(x1,x2) & n_gang(x2)) & n_people(x1) & a_young(s1) & Theme(s1,x1))