社区领袖们正在努力减少黑人群体内部的暴力事件。

Community leaders are working to reduce ___black-on-black violence within the neighborhood.

这家商店的橱窗展示了一件全黑的black-on-black西装，细节处用不同质感的黑色面料拼接。

The store window displayed a ___black-on-black suit with different textured black fabrics at the details.