People are taking pictures.
A group of cats in an alley.
Cats are not people.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_take(e1) & n_picture(x2) & n_people(x1))
exists x1 x2 x3.(a_topic(x1) & of(x1,x2) & in(x2,x3) & n_alley(x3) & n_cat(x2) & n_group(x1))