Guests at a wedding in a park, by a lake.
 Guests at a wedding by a lake.
The guest are at a wedding in a park but the guests aren't necessarily by a lake; the park could be what is by the lake.
exists x1 x2 x3 x4.(a_topic(x1) & at(x1,x2) & in(x2,x3) & by(x3,x4) & n_lake(x4) & n_park(x3) & n_wedding(x2) & n_guest(x1))
exists x1 x2 x3.(a_topic(x1) & at(x1,x2) & by(x2,x3) & n_lake(x3) & n_wedding(x2) & n_guest(x1))