这场灾难清楚地证明需要加强管控。

This disaster is a clear ___demonstration of the need for tighter controls.

她的快速康复有力地证明了该治疗方法的有效性。

Her quick recovery is a powerful ___demonstration of the treatment's effectiveness.

稳定的经济增长是新政策取得成功的有力证明。

The steady economic growth is a solid ___demonstration of the new policy's success.