I.
A—air traffic control system J—safety precaution measure
B—armed police K—safety control device
C—crime prion L—security command center
D—entry requirement M—security service
E—international criminal police organization N—security control center
F—level of security O—security personnel
G picket line P—valid documents
H—police station Q—security monitoring and control
I—patrolling vehicle

I.
A—air traffic control system J—safety precaution measure
B—armed police K—safety control device
C—crime prion L—security command center
D—entry requirement M—security service
E—international criminal police organization N—security control center
F—level of security O—security personnel
G picket line P—valid documents
H—police station Q—security monitoring and control
I—patrolling vehicle（） 巡逻车（）武装警察

I.
A—air traffic control system J—safety precaution measure
B—armed police K—safety control device
C—crime prion L—security command center
D—entry requirement M—security service
E—international criminal police organization N—security control center
F—level of security O—security personnel
G picket line P—valid documents
H—police station Q—security monitoring and control
I—patrolling vehicle