A girl is singing while jumping in the air.
A girl is jumping in the air while singing on her birthday.
Just because a girl is singing while jumping in the air does not mean she is jumping and singing on her birthday.
exists e2 e1 x1 x2.(n_air(x2) & while(e1,e2) & in(e2,x2) & Actor(e2,x1) & v_jump(e2) & Actor(e1,x1) & v_sing(e1) & n_girl(x1))
exists e2 e1 x1 x2 x3.(n_birthday(x3) & of(x3,x2) & n_female(x2) & n_air(x2) & while(e1,e2) & on(e2,x3) & Actor(e2,x1) & v_sing(e2) & in(e1,x2) & Actor(e1,x1) & v_jump(e1) & n_girl(x1))