千载难逢的英文：
[Literal Meaning]
thousand/year/difficult/meet
unlikely to occur once even in a thousand years

[解释]
一千年里也难碰到一次。形容机会极其难得。

[Explanation]
extremely seldom; hardly at all or hardly ever

[例子]
能够去美国留学，对他这样一个穷孩子来说，是一个千载难逢的机会。

[Example]
Going to the US to study is a very rare opportunity for such a poor boy as him.

[英文等价词]
once in a blue moon
occuring only once in a thousand years

This opportunity is too good to waste.
这个机遇千载难逢，绝不能错过。

This is a chance once in a blue moon.
这可是个千载难逢的好机会呀！

She was rare, a perfect creation, a work of purest art.
她是千载难逢、完美无瑕的创作，是最为地道的艺术杰作。

The end of cold war gave EU a very rare historic opportunity to reunite Europe.
冷战的终结使欧盟获得了再次统一欧洲的千载难逢的历史性机遇。