Two girls with red shirts tied at their waists are laughing while looking down.
Girls are laughing, looking down
The fact that the girls are laughing and looking down is in consequence of sentence irrespective of the number of girls mentioned.
exists e1 e3 e2 s1 s2 x1 x2 x3 x4.(while(e2,e3) & a_down(s2) & Manner(e3,s2) & Actor(e3,x1) & v_look(e3) & Actor(e2,x1) & v_laugh(e2) & with(x1,x2) & at(e1,x4) & n_waist(x4) & of(x4,x1) & n_thing(x1) & Theme(e1,x3) & v_tie(e1) & (x2 = x3) & n_shirt(x2) & a_red(s1) & Theme(s1,x2) & n_girl(x1) & card_eq_2(x1))
exists e1 e2 s1 x1.(for(e1,e2) & a_down(s1) & Manner(e2,s1) & Actor(e2,x1) & v_look(e2) & Actor(e1,x1) & v_laugh(e1) & n_girl(x1))