Three couples are dancing on stage with arms on each other's shoulders.
People are dancing on stage with arms on each other's shoulders.
People is plural for more than one person, so it be translated as three couples.  The fact that they are all dancing on the stage with arms on each others shoulders makes it appear to be the same people.
exists e1 x1 x2 x3.(all x4 x5.((n_shoulder(x5) & of(x5,x4) & n_other(x4)) -> on(e1,x5)) & with(e1,x3) & n_arm(x3) & on(e1,x2) & n_stage(x2) & Actor(e1,x1) & v_dance(e1) & n_couple(x1) & card_eq_3(x1))
exists e1 x1 x2 x3.(all x4 x5.((n_shoulder(x5) & of(x5,x4) & n_other(x4)) -> on(e1,x5)) & with(e1,x3) & n_arm(x3) & on(e1,x2) & n_stage(x2) & Actor(e1,x1) & v_dance(e1) & n_people(x1))