circumferential crack in plate

例句：

1. 1.The circumference of the circle is 20 units.
   这个圆的周长是20单位。
2. 2.The circumference of the wire is 15 meters.
   这根线的周长是15米。
3. 3. The circumference of the circle is twice as long as its diameter.
   这个圆的周长是直径长度的两倍。