on a need-to-know basis idiom
仅限于人们需要知道的东西
If you tell people something on a need-to-know basis, you only tell them the facts they need to know at the time they need to know them, and nothing more.
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。