People dancing at a party.
Some people are dancing.
Some people are dancing, and its normal to dance at a party.
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.(Actor(e1,x1) & v_dance(e1) & n_people(x1))