n.圆周；周围；周长
He went jogging around the circumference of the reservoir every morning. 他每天早晨绕着水库周围慢跑。
This tree has a circumference of 6 feet. 这棵树周长六英尺。
The circumference of the earth is almost 25,000 miles. 地球的圆周长约为两万五千英里。
