A woman is on a carnival swing ride.
a woman is at the carnival
A woman at a carnival doesn't have to be on a swing ride.
exists p1 x1.(exists s1 x2 x3.(on(x1,x2) & n_ride(x2) & of(x2,x3) & n_swing(x3) & a_carnival(s1) & Theme(s1,x2)) & n_woman(x1))
exists p1 x1 x2.(n_carnival(x2) & at(x1,x2) & n_woman(x1))