ad lib

The comedian had to ad lib for ten minutes when the microphone system failed.

(Chinese) 麦克风系统出故障时，喜剧演员不得不即兴表演了十分钟。

Great jazz musicians often ad lib their solos during a live performance.

(Chinese) 伟大的爵士音乐家经常在现场演出时即兴演奏独奏。

The actor's funniest line was actually an ad lib that wasn't in the original script.

(Chinese) 那位演员最搞笑的一句台词其实是剧本里没有的即兴发挥。

During his speech, he threw in a few clever ad libs to keep the audience engaged.

(Chinese) 他在演讲中加入了一些巧妙的即兴之辞，以保持观众的兴趣。