1.   City authorities were quick to crack down on the rioters.

2.   From Los Angeles to Athens, city authorities have tried to enact measures to limit exhaust emissions.

3.   Our city authorities are resolved that the new school will be built within six months.

4.   Residents jammed the switchboard of city authorities asking whether it was safe in the area.

5.   The city authorities are bringing in new parking regulations next month.

6.   The city authorities are trying to work out a practical solution to the problem of homelessness.

7.   The city authorities complained that low-flying aircraft were endangering public safety.

8.   The city authorities gave permission for the rally to take place.

9.   The city authorities have abandoned their plans to host the Super Bowl.