C. Read the passage and fill in the blanks with proper words: (7分) ★★ Trees clean the air, soil and water, the Earth a livable place. If you want to save trees, you can help by protecting those that grow in your o____65____neighbourhood, and planting more when you see trees cut down. Efficient use of paper p____66____is important, too. If you truly care about saving trees, consider getting involved in an organization working to save the world’s remaining forests. The trees i____67____air quality, reduce erosion and absorb noise. Big trees protect cities from getting too h____68____by cooling the environment through shade and evaporation. W____69____trees, areas experience what’s called a heat island effect, with streets and buildings retaining heat and forcing people to use extra power to cool their homes. No matter where you live, you can start helping your town right away by saving trees. As a general rule, large, mature (成熟的) trees provide more benefits than small, y____70____trees. That’s why it’s important to save as many older trees as possible. Learning about proper tree maintenance will help you become a b____71____advocate (提倡者) for trees. There’s a right way and a wrong way to take care of trees over the years, and if you know the difference you can educate people around you. 65. ____66. ____67. ____68. ____69. ____70. ____71. ____