A pair is performing in a ballet.
Two people are dancing.
Dancing equates to performing.
exists e1 x1 x2.(in(e1,x2) & n_ballet(x2) & Actor(e1,x1) & v_perform(e1) & n_pair(x1))
exists e1 x1.(Actor(e1,x1) & v_dance(e1) & n_people(x1) & card_eq_2(x1))