at the drop of a hatIMMEDIATELYimmediately and without pausing to think about what you are going to do 立即,不假思索,毫不迟疑 Some of these corporations threaten to sue at the drop of a hat. 这些大公司中有几家威胁说要马上提起诉讼。
at the drop of a hat• He's willing to organize anything guests want at the drop of a hat.
→ at the drop of a hat at drop2(1)