Bread and butter

請問在 "Just explain the bread and butter of your report. You don't have to go into

details." 這句話中"bread and butter"的意思是什麼?

以前學到的意思是"生計",可是在這句看起來卻好像是"大綱、概述"之類的意思

請問這句的意思到底是哪個呢?
1 個解答 1