periblem

例句：

1. 1.The perimeter of the circle is 2π radians.
   圆的周长是2π弧度。
2. 2. The edges of the table are smooth and polished.
   桌子的边缘光滑且经过打磨。
3. 3. The margin of the book is thin and delicate.
   书的边缘薄而精致。