Question 12: Earth Hour _________attention to climate change and global energy issues, and promotes green activities worldwide.

A. attracts B. draws C. paints D. writes

Question 13: There are lots of things we can all do to ____ the environment.

A. enhance B. protect C. make D. build

Question 14: The gradual rise in the Earth's temperature is known as ____.

A. greenhouse effect B. global warming C. ozone layer D. acid rain

Question 15: All the different plants and animals in a natural community are in a state of __________.

A. peace B. balance C. energy D. pollution

Question 16: Air pollution is a ____________of fossil fuel burning by motor vehicles, factories, aircraft and rockets.

A. product B. example C. harm D. consequence

Question 17: Air pollution is a ___________ problem in many major cities.

A. practical B. global C. serious D. endangered

Question 18: Global warming is making _________weather events, such as hurricanes and droughts.

A. extreme B. positive C. sustainable D. climatic