A group of children are standing with their arms raised over their heads.
A group of children are holding their hands above their heads.
holding their hands above their heads is another way to say arms raised over their heads. If their arms are over their heads, their hands would be too.
exists e1 e2 x1 x2 x3 x4 x5.(with(e1,x3) & over(e2,x5) & n_head(x5) & of(x5,x1) & n_thing(x1) & n_thing(x1) & Theme(e2,x4) & v_raise(e2) & (x3 = x4) & n_arm(x3) & of(x3,x1) & Actor(e1,x1) & v_stand(e1) & of(x1,x2) & n_child(x2) & n_group(x1))
exists e1 x1 x2 x3 x4.(above(e1,x4) & n_head(x4) & of(x4,x1) & n_thing(x1) & n_thing(x1) & Theme(e1,x3) & Actor(e1,x1) & v_hold(e1) & n_hand(x3) & of(x3,x1) & of(x1,x2) & n_child(x2) & n_group(x1))