needle sharpener

例句：

1. 1. This needle sharpener is very useful for cleaning my sewing machine.
   这个针尖磨刀石对我清理缝纫机非常有用。
2. 2. The sharpener is designed to make the needles of your scissors sharper.
   这款磨刀石的设计是让你的剪刀的针尖更锋利。
3. 3. I use a needle sharpener to keep my knitting needles sharp and ready for use.
   我用一个针尖磨刀石来保持我的钩针针尖锋利，随时准备使用。