by word of mouth idiom
口头上的
in speech but not in writing
All the orders were given by word of mouth so that no written evidence could be discovered later. 所有命令都是口头传达的，所以事后找不到任何书面证据。
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。