rise to the occasion   (TTS發音)

prove to be adequate for the purpose or situation 證明能做某事或應付某局面

    When the invited speaker did not arrive，the chairman rose to the cocasion and gave an excellent unprepared speech. 當被邀請的演講者沒有到時，主席隨機應變，作了一個非常出色的即席演講。