The story is just a blue moon.

這個故事根本就是件不可能的事.

He gives us a treat only once in a blue moon.

他招待我們一頓可真是千載難逢.

By living a blue moon with the Indians, he was assimilated to them in his thinking and actions.

由于長期和印第安人共同生活, 他在思想和行動上都被他們同化了.

Something that happens once in blue moon almost never happens.

那種罕見的事情幾乎不會發生.

We also did all the work for the Blue Moon Race.

我們也為藍色月亮比賽做了所有的工作.

Where have you been? I haven't seen you in a blue moon.

你到哪兒去了? 我好久沒見到你了.

That sort of thing only happens once in a blue moon.

這種事情難得發生一次.

It was an opportunity that comes once in a blue moon.

這種機會來一次可太難了.

He gets drunk only once in a blue moon.

他難得喝醉酒.

This is a chance once in a blue moon.

這可是個難得的機會.