perimeters
n. 周边( perimeter的名词复数 ); 周围; 边缘; 周长
The perimeter of an area of land is the whole of its outer edge or boundary.
...the perimeter of the airport...
机场四周
Officers dressed in riot gear are surrounding the perimeter fence.
身穿防暴服的警察正在包围外围的栅栏。
Examples include outdoor perimeters , traffic monitoring, tunnels, and car parks.
例子像户外围墙; 交通监视; 隧道和停车场.