Just when this will happen is anyone's guess.

谁也拿不准这件事什么时候会发生。

《柯林斯英汉双解大词典》

He always turns up just when you least expect him.

他总是在你最意料不到的时候出现。

《牛津词典》

Just when she thought she was home free, her father spoke from behind her.

就在她认为已经大功告成的时候，身后传来她爸爸说话的声音。

《柯林斯英汉双解大词典》

Just when I tell you to go, you leave me. You know you can't leave a schoolroom without raising your hand, no matter where you're going."

VOA: special.2009.07.19

This becomes really, really important, not just when you're starting a business but when you're trying to grow that business.

这变得非常，非常重要，不仅对创业重要,而且对扩大业务也很重要。

斯坦福公开课 - Twitter之父Jack.Dorsey演讲：好奇和灵感的力量课程节选

And just when you wake up, think, "Right, what do I want to wear today?"

当你醒来的时候，会想，“对了，今天我想穿什么呢？”

时尚让人兴奋 - SpeakingMax英语口语达人

In the film and in life, that can happen even just when people see each other.

NPR: 'Low and Behold': A Post-Disaster New Orleans

And in 2008, just when the economy started to unravel, the perfect opportunity arose.

FORBES: Tyler Florence Is Cooking Up An Entrepreneurial Empire

This means that the courts are limiting access just when Americans need more adjudication.

ECONOMIST: The judicial system