perimetern.周长;周界;边缘
perimeter ditch周边沟,围护沟
perimeter light外围灯
perimeter alarm周界报警
perimeter shear环向剪力,周剪力
perimeter stops周边挡
perimeter frame边框式车架
perimeter paper视野计用纸
perimeter trench围护沟
Perimeter nation周边国家
perimeter effect周界影响