catch someone on the wrong foot idiom
令（某人）措手不及
If something catches you on the wrong foot, you are not prepared for it.
I hadn't expected the question and it caught me on the wrong foot. 我没有预料到这个问题，它使我措手不及。
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。