weak at the knees
腿软
口语·描述强烈情感
英文释义
physically or emotionally affected by something in a powerful or overwhelming way
例句
When he saw her walk in, he felt weak at the knees.
典故来源
源自生理反应，因强烈情感（如爱慕、恐惧）导致膝盖无力，形容激动或紧张。