once in a blue moon

含义

very rarely

非常难得地.

例句

1. 1We only eat out once in a blue moon, so tonight feels special.
2. 2My brother lives in Canada, so I see him once in a blue moon.
3. 3Priya is always on time; she's late once in a blue moon, and only when the trains are cancelled.
4. 4Does Grandad still go to the cinema, or only once in a blue moon these days?
5. 5The big supermarket is miles from the village, so the family drives there once in a blue moon.

语法

短语不变化，通常放在分句末尾。