Source: Extra Practice
What does the idiom 'Once in a blue moon' mean?
Options
Option A is correct
Something that happens very rarely.
Option B
Something that happens every month on a full moon day.
Option C
A very sad and gloomy day.
Option D
An event that occurs only during the night.
Explanation
The idiom 'Once in a blue moon' is used to describe an event that happens extremely rarely or almost never. It has no physical connection to the moon's phases, nighttime, or feelings of sadness, making options 2, 3, and 4 incorrect.