smooth bore

例句：

1. 1. The engineer useda smooth bore to drill through the concretewall.
   工程师使用一个光滑的钻头来钻透混凝土墙。
2. 2. Thesmooth bore made it easyto remove the screws.
   光滑的钻头使得移除螺丝变得容易。
3. 3. The smooth bore allowed for precise cuttingand shaping of materials.
   光滑的钻头允许对材料进行精确的切割和成型。