hollow boring bit

例句：

1. 1.The engineer used a hollow boring bit todrill through the concrete wall.
   工程师使用空心钻头钻透混凝土墙。
2. 2. The hole wastoo small for the hollow boring bit tofit in.
   这个洞太小，无法让空心钻头进入。
3. 3.The hollow boring bit was usedto remove the old paint from thewalls.
   空心钻头被用来从墙上去除旧油漆。