Two children are sitting while one is standing over them.
There are three children in the sandbox.
The children could be anywhere other than a sandbox.
exists e1 p1 x1.(exists e2 x2.(over(e2,x1) & Actor(e2,x2) & v_stand(e2) & n_thing(x2) & card_eq_1(x2)) & n_thing(x1) & while(e1,p1) & Actor(e1,x1) & v_sit(e1) & n_child(x1) & card_eq_2(x1))
exists p1 x1 x2.(n_sandbox(x2) & in(p1,x2) & exists x3.((x1 = x3) & n_child(x3) & card_eq_3(x3)))