着丝点

例句：

1. 1. The spinner carefully places the bobbin at the centre of the wheel.
   纺纱者小心地把卷轴放在轮子的中心。
2. 2. The fibres are tightly packed together at the centre of the fabric.
   纤维紧密地聚集在织物的中心。
3. 3. The scientist found the centre of the cell to be rich in nutrients.
   科学家发现细胞的中心富含营养。