A body of persons making up such a department, trained in methods of law enforcement and crime prevention and detection and given the authority to maintain the peace, safety, and order of the community.警察组成这样一个部门的一群人,他们被专门训练来掌握执行法律和防止并侦破犯罪行为的方法,被授予维护一个社区的和平、安全和秩序的职权