counterguard

例句：

1. 1. The soldiers were busy constructing a counterguard to protect the city from intruders.
   士兵们忙着建造一道防线以保护城市免受入侵者侵扰。
2. 2.The government has implemented strict counterguard measures to prevent any further attacks.
   政府已经实施了严格的防范措施，以防止任何进一步的攻击。
3. 3. The counterguard system is designed to provide immediate response to any security breaches.
   这种防护系统旨在对任何安全漏洞提供即时响应。