at the drop of the hat

• 马上,很乐意地

at the drop of the hat的用法和样例：

例句

1. You want to see a doctor at once.
   你必须马上去看医生。
2. I was vaguely astride the only horse.
   我象腾云驾雾似地跨在仅有的一匹马上。
3. He can sing any song at the drop of a hat.
   他随时能唱任何一首歌。
4. The timetable is subject to change without notice.
   本时刻表随时可能改变，不另行通知。

词汇搭配

• at the drop of the hat 马上,很乐意地...
• at the drop of a hat 一发出信号(一碰)...