A boy and girl are dancing.
A boy and a girl are dancing at the school ball.
You cannot infer that the boy and girl are at a school ball.
exists e1 x1 x2 x3.(Actor(e1,x1) & v_dance(e1) & n_girl(x3) & n_boy(x2) & subset_of(x3,x1) & subset_of(x2,x1))
exists e1 x1 x2 x3 x4 x5.(n_ball(x4) & of(x4,x5) & n_school(x5) & at(e1,x4) & Actor(e1,x1) & v_dance(e1) & subset_of(x3,x1) & n_girl(x3) & subset_of(x2,x1) & n_boy(x2))