?不成文惯例
... unwritten code 不成文法典 unwritten conventions 不成文惯例 Unwritten History 空白的历史 ...
不成文惯例
My view is that it's exactly that culture of unwritten conventions, unspoken rules, nods and winks that has got us into this trouble in the first place, and I've arrived at the conclusion that the Speaker must go.
BBC: The Speaker must go
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。