A light-bulb moment is when you have a sudden realization¹ about something. It's a moment of sudden inspiration, revelation, or recognition. 

“电灯泡时刻”是指你突然醒悟的那一瞬间，指的是突然灵光闪现、受到启发，或者意识到什么的时刻。

 

Light-bulb moment is an event when one suddenly understands something even if the concept had been explained several times before. 

有时一种概念之前已经解释了很多遍，但突然你就理解了，这就是“电灯泡时刻”。