once in a blue moon

副词 adv.
中文释义

英文释义

副词 adv.
  1. Very rarely; very infrequently. idiomatic,not-comparable
    — We are no advocates for the eternal system of producing foreign operas to the exclusion of the works of English composers, but once in a blue moon such a thing may be allowed.

词源

See blue moon. First use appears c. 1833. See citation below.
0 次浏览 数据来源: Wiktionary