black marrow

例句：

1. 1. The black marrow of the bone is where blood cells are produced.
   骨的黑色部分是血细胞产生的地方。
2. 2.He had a black marrow disease that made his bones weak.
   他患有一种骨髓疾病，导致他的骨头变得虚弱。
3. 3.The black marrow in the marrow cavity helps to produce new blood cells.
   骨髓腔中的黑色骨髓有助于生成新的血细胞。