think on your feet
US /θɪŋk ɑn jʊər fiːt/
UK /θɪŋk ɑn jʊər fiːt/

1.
随机应变, 快速反应, 即兴发挥
to be able to think and react quickly, especially in an unexpected situation
:
•
A good salesperson needs to be able to think on their feet.
一个好的销售人员需要能够随机应变。
•
When the unexpected question came, she had to think on her feet to give a suitable answer.
当意想不到的问题出现时,她不得不随机应变才能给出合适的答案。