I think the cities of tomorrow also need to consider the availability of open space, ____? A. do I B. don't I C. do they D. don't they

This is your essay on smart cities by 2050, ____? A. is this B. isn't this C. is it D. isn't it

Many scientists are cautiously ____ that the earth can feed more than nine billion people. A. interested B. pessimistic C. optimistic D. negative

If I ____ this exam, I'll go to the university next summer. A. pass B. to pass C. had passed D. passed

The Saudi government is investing billions in ____ to support the enormous influx of people in Mecca. A. streets B. roads C. bridges D. infrastructure

China has already been experimenting with ways to make its cities more ____ for the last two decades. A. sustain B. sustainable C. survival D. available

Across the globe, nations are preparing for water scarcity, ____? A. are they B. aren't they C. will they D. won't they

Your grandfather was a millionaire, ____? A. was he B. is he C. wasn't he D. isn't he

Copenhagen has been voted the most ____ city in the world several times. A. ecological friendly B. ecologically soundly C. eco-friendly D. friendly ecologically

That was Ann on the phone, ____? A. was it B. was that C. wasn't that D. wasn't it

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

Nothing serious will be expected in the process of building our smart city, ____? A. will it B. won't it C. will they D. won't they

____ there are some more ideas, we can end the meeting now. A. Unless B. If C. As if D. In case