A little girl is vacuuming the floor while two other children look on.
The children are in the house alone.
Just because a little girl is vacuuming the floor while two other children look on does not mean that they are in the house alone.
exists e1 p1 s1 x1 x2 x4.(n_child(x4) & n_floor(x2) & exists e2 p2 x3.(exists s2.(Theme(s2,x3) & a_on(s2)) & Topic(e2,p2) & Actor(e2,x3) & v_look(e2) & -(x3 = x4) & n_child(x3) & card_eq_2(x3)) & while(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_vacuum(e1) & n_girl(x1) & a_little(s1) & Theme(s1,x1))
exists p1 x1 x2.(n_house(x2) & n_child(x1) & in(x1,x2) & r_alone(x2))