People are at a party at night.
People a drinking and playing games
The fact that people are at a party doesn't mean that people are drinking and playing games.
exists p1 x1 x2.(at(p1,x2) & n_night(x2) & exists x3.(at(x1,x3) & n_party(x3)) & n_people(x1))
exists s1 x1 x2.(a_topic(s1) & subset_of(x1,s1) & n_game(x1) & of(x1,x2) & n_playing(x2) & all x3.(n_drinking(x3) -> exists x4.(subset_of(x4,s1) & for(x4,x3) & n_people(x4))))