It means police patrol in vehicles, on foot or on bicycles regularly or at random in day or night time covering every corner of the city like a net.

• 警:它的意思是指警察不管是白天还是黑夜通过机动车,步行或者骑自行车进行常规和乱线巡逻,其像网一样覆盖全市的每个角落。