公安

例句：

1. 1. The police are investigating the crime scene.
   警方正在调查犯罪现场。
2. 2. He served as a police officer for many years.
   他担任过多年的警察。
3. 3. Public security is crucial in maintaining law and order.
   公共安全对于维护法律和秩序至关重要。