转笔刀

例句：

1. 1. I need to sharpen my pen before I start writing.
   我需要先磨尖我的钢笔才能开始写字。
2. 2. The pencil sharpener is very easy to use.
   这个铅笔磨刀非常易用。
3. 3. She bought a new pencil sharpener for her son's birthday.
   她为儿子的生日买了一个新的铅笔磨刀。