The tautology used by Marx in this explanation is that each industry contributes to the total surplus its entire output minus the amount used up in supporting labor.

• 马克思在解释中反复说到的是，每一个产业部门都对剩余价值总额有贡献，其贡献是它的整个产出减去为用来维持劳动力而消耗掉的量。