一去不复返 (yī qù bú) — (set phrase) gone never to return; once gone, never to be seen again; (figurative) irretrievably lost (of youth, opportunities, an era, etc.)

Definition

Examples

• 青春一去不复返，所以我们要好好珍惜每一天。
  Qīng chūn yī qù bú, suǒ yǐ wǒ men yào hǎo hǎo zhēn xī měi yì tiān.
  Youth never returns, so we must cherish every day.
• 那个纯真的年代已经一去不复返，只能留在记忆里了。
  Nà ge chún zhēn de nián dài yǐ jīng yī qù bú, zhǐ néng liú zài jì yì lǐ le.
  That innocent era has gone never to return; it can only remain in memory.
• 机会一去不复返，一旦错过就再也不会有了。
  Jī huì yī qù bú, yí dàn cuò guò jiù zài yě bú huì yǒu le.
  Opportunities never return; once you miss them, they won't come again.