The sales director spoke impromptu at the meeting when the keynote speaker's flight was delayed.

主講人的班機延誤，業務總監便在會議上即興發言。

Our tour guide performed impromptu for the passengers while the bus waited at customs.

巴士在海關等候時，我們的導遊即興為乘客表演。

She answered the reporter's questions impromptu, since the press release had not been finalized.

由於新聞稿尚未定案，她即興回答了記者的提問。