There are a lot of kids walking on train tracks surrounded by trees.
THE grass was green
The area is surrounded by trees but it does not imply that there are grass as well.
exists p1 x1 e2 e1 x2 x3 x4 x5 x6 x7 x8.((x1 = x2) & of(x2,x3) & on(e1,x5) & Actor(e2,x8) & n_tree(x8) & Theme(e2,x7) & v_surround(e2) & (x5 = x7) & n_track(x5) & of(x5,x6) & n_train(x6) & Actor(e1,x4) & v_walk(e1) & (x3 = x4) & n_kid(x3) & n_lot(x2))
exists s1 x1.(n_grass(x1) & Theme(s1,x1) & a_green(s1))