A child on a rock in a stream.
The girl balances on the rock in the stream.
Not all who are a child are a girl. Just because a child is on a rock doesn't imply balances.
exists x1 x2 x3.(a_topic(x1) & on(x1,x2) & in(x2,x3) & n_stream(x3) & n_rock(x2) & n_child(x1))
exists e1 x1 x2 x3.(n_stream(x3) & n_rock(x2) & n_girl(x1) & on(e1,x2) & in(x2,x3) & Actor(e1,x1) & v_balance(e1))