A child on a swing.
A kid on a swing set.
A child refers to a kid
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_swing(x2) & n_child(x1))
exists x1 x2 x3.(a_topic(x1) & on(x1,x2) & n_set(x2) & of(x2,x3) & n_swing(x3) & n_kid(x1))