shaft of ulna

例句：

1. 1. The carpenter used a wooden shaft to saw the wood.
   木匠用一根木杆来锯木头。
2. 2. The tree's trunk is a sturdy shaft that supports the branches.
   这棵树的树干是一个结实的轴，支撑着树枝。
3. 3. The engineer designed a new shaft for the elevator.
   工程师为电梯设计了一个新的轴。