People are in a grocery store.
People are at a grocery store.
In the grocery is inside. At the grocery is around.
exists p1 x1.(exists x2 x3.(in(x1,x2) & n_store(x2) & of(x2,x3) & n_grocery(x3)) & n_people(x1))
exists p1 x1.(exists x2 x3.(at(x1,x2) & n_store(x2) & of(x2,x3) & n_grocery(x3)) & n_people(x1))