bread and butter

For the small repair shop, restoring old radios remained its bread and butter even as it began selling new speakers.

对这家小维修店来说，修复旧收音机仍是其主要收入来源，尽管它也开始销售新音箱。

And that's something that is very bread and butter to Galileo, and we focus a lot on that day in and day out.

而这对Galileo来说是非常基本、赖以生存的业务，我们日复一日地在这方面投入很多。