Pollution and heavy traffic are common problems in ____ cities.

The ____ of living in some places can be very high. Prices in London are particularly exorbitant.

China has already been experimenting with ways to make its cities more ____ for the last two decades.

We will need new technologies to generate energy and use it in clean and safe ways, only from fully ____ sources.

Copenhagen has been voted the most ____ city in the world several times.

Since 2007, Boston police have been using Shotspotter, a system that allows them to ____ the location of shots fired immediately.

Vancouver is often considered to be one of the most ____cities in the world.

____ structure in Hanoi will be changed with the development of satellite areas.

Telecommunications and cloud computing will ____ transportation for moving ideas and intellectual property.