before you could say Jack knife

• 马上；立即

before you could say Jack knife的用法和样例：

例句

1. You look not well,you'd better go to see a doctor.
   你脸色不太好，最好马上去看一下医生。
2. Right off the bat you should have put two and two together.
   你本应该马上作出合理推论的。
3. I desire you to set to work at once.
   我希望你立即开始工作。
4. Please wire as soon as you hear.
   你一听到就请立即拍电报给我。