1. to help tackle the nation’s chronic smog/pollution problem
4. There are some large greenhouses around the bottom of the tower. Polluted air is sucked into the greenhouses and heated by the sun. Then the hot air rises through the tower and passes through several cleaning filters.
5. Cao is the head of the research for the project.
6. (i) assessment
8. Any one of:
The Beijing tower uses more energy/The Beijing tower uses coal-generated electricity. / The Beijing tower is smaller./The Xian tower requires very little power to run./The Xian tower is much taller.
10. The tower is tall/eye-catching/quiet/improved air quality.