Three women are singing, and being photographed.
Three sisters are singing while being photographed.
The relationship between the women may be something other than sisters.
exists e2 e1 x1 x2.(Theme(e2,x2) & v_photograph(e2) & n_woman(x2) & card_eq_3(x2) & Actor(e1,x1) & v_sing(e1) & n_woman(x1) & card_eq_3(x1))
exists e2 e1 x1.(while(e1,e2) & Theme(e2,x1) & v_photograph(e2) & Actor(e1,x1) & v_sing(e1) & n_sister(x1) & card_eq_3(x1))