center circle of pin holes

例句：

1. 1.The center circle of pin holes is the most critical part of the design.
   中心圆孔是设计中最关键的部分。
2. 2. The center circle of pin holes is used to hold the paper together during printing.
   中心圆孔用于在印刷过程中固定纸张。
3. 3. The center circle of pin holes is a crucial element in the manufacturing process.
   中心圆孔是生产过程中至关重要的元素。