N-UNCOUNT 生计;谋生之道;主要收入来源 Something that is the bread and butter of a person or organization is the activity or work that provides the main part of their income.
The mobile phone business was actually his bread and butter. 移动电话业务实际上是他的主业。
ADJ 最基本的;影响到大多数人的 Bread and butter issues or matters are ones which are important to most people, because they affect them personally.
The opposition gained support by concentrating on bread-and-butter matters. 反对党关注与大多数人切身利益相关的问题,从而赢得了人们的支持。