People dancing at a party.
People are drinking cocktails at the dinner party.
Drinking and dancing are two different activities.
exists e1 x1 x2 x3.(a_topic(x1) & at(e1,x3) & n_party(x3) & Actor(e1,x2) & v_dance(e1) & (x1 = x2) & n_people(x1))
exists e1 x1 x2 x3 x4.(n_party(x3) & of(x3,x4) & n_dinner(x4) & at(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_drink(e1) & n_cocktail(x2) & n_people(x1))