千载难逢

qiān zǎi nán féng

once in a lifetime

Character by character

千qiān
thousand

载zǎi
years

难nán
hard

逢féng
meet

这可是千载难逢的好机会，别错过了。

This is a once-in-a-lifetime chance — don’t miss it.

Tone: neutral.

For good chances only, and 载 is zǎi (year) here; for disasters say 百年不遇.

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