ad-lib performance 即兴表演
ad-lib speech 即兴演讲
improvise ad-lib 即兴发挥
A: The actor forgot his lines during the play.
A：演员在演戏时忘词了。
B: Don't worry, he can ad-lib the scene.
B：别担心，他可以即兴表演这一段。
1) 即兴创作
2) 临时发挥
3) 随口说出
1. 即兴表演或说话
verb
1. To speak or perform without preparation.
Synonym: improvise
noun
1. Something that is improvised.