尤指在公共场合接受提问或辩论时思维敏捷，对答如流的样子。

To be able to think clearly in times of stress, especially when forming a solution to a pressing problem.

在压力下能够清晰地思考，特别是在解决一个紧迫的问题时。

I'd never heard about the company before, so I had to think on my feet.

我以前从来没有听说过这家公司，只好临时随机应变。