Two boys playing soccer go after a ball.
Some boys are playing soccer.
playing soccer go after a ball shows that they are  playing soccer.
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & after(e1,x5) & n_ball(x5) & Theme(e1,x3) & Actor(e1,x2) & v_play(e1) & n_go(x3) & of(x3,x4) & n_soccer(x4) & (x1 = x2) & n_boy(x1) & card_eq_2(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_soccer(x2) & n_boy(x1))