once in a blue moon
英 [wʌns in ə blu: mu:n] 美 [wʌns ɪn e blu mun]

adv.

千载难逢地；俟河之清；百年不遇；

英英释义

Once in a Blue Moon

• Once in a Blue Moon is an album by the Phil Beer Band released in 2001. It is their latest recorded album using this band name.

以上来源于:Wikipedia

双语例句

1. It was in the days when motorcars were rare.
   那是在汽车还罕见的时代。
2. Several rare birds have been sighted in this area.
   本地区已发现了几种罕见的鸟。

权威例句

Once in a blue moon
Once in a blue moon
Once in a Blue Moon
Inadvertent chlorpropamide hypoglycemia--no longer once in a blue moon?
Cutaneous metastasis in endometrial cancer: once in a blue moon – case report
Once in a Blue Moon: Airmen in Theater Command
Once in a blue moon: detection of 'bluing' during debris transits in the white dwarf WD1145+017
Once in a Blue Moon … Rare Adnexal Tumor: From the Clinical and Videodermoscopical Aspects to the Mohs Surgery and the Histological...
Once in a Blue Moon Lodge: A Novel
Once in a Blue Moon Lodge
The origin of the expression “once in a blue moon”. Can the moon really be blue?
Once in a Blue Moon Lodge: A Novel
Once in a Blue Moon Lodge: A Novel