People on an amusement park ride.
There are people at the amusement park.
if the people are on an amusement park ride, it is implied that they are at the amusement park, as an amusement park has amusement park rides.
exists x1 x2 x3 x4.(a_topic(x1) & on(x1,x2) & n_ride(x2) & of(x2,x4) & n_park(x4) & of(x2,x3) & n_amusement(x3) & n_people(x1))
exists p1 x1 x3 x4.(n_park(x3) & of(x3,x4) & n_amusement(x4) & exists x2.((x1 = x2) & at(x2,x3) & n_people(x2)))