wolf-proof fence

例句：

1. 1. The new safety fence has been installed around the playground.
   新安装的安全栅栏已经围绕操场。
2. 2. He built a tall security fence to keep his property safe.
   他建造了一座高高的保安栅栏来保护他的财产。
3. 3. The police cordoned off the area with a wolf-proof fence.
   警方用一道防狼栅栏封锁了那个区域。