A—Air traffic control system B—Armed police
C—Crime prion D—Entry requirement
E—International criminal police organization F—Level of security
G—Picket line H—Police station
I—Patrolling vehicle J—Safety precaution measure
K—Safety control device L—Security command center
M—Security service N—Security control center
O—Security personnel P—Valid documents
Q—Security monitoring and control ______巡逻车 ______武装警察