Tropical forests have supplied us with very many sorts of plants for food, (17)__________ and industry. They could probably supply man more. They also reduce floods and droughts, keep water clean, and slow down the Greenhouse Effect, (18)__________ the tropical forests are being destroyed to make (19)__________ for things like farms, ranches, mines and hydroelectric (20)__________. About 20 million hectares are lost each year – an area more than twice the size of Austria. The World Wildlife Fund is working to (21)__________ and save the forests that are in danger; to plant new trees for fuel wood and to slow down the Greenhouse Effect; and to (22)__________ governments to think about the forests and their importance when giving international aid.
- A. hospitals B. medicine C. doctors D. surgeons
- A. so B. though C. because D. but
- A. place B. places C. room D. rooms
- A. energy B. sources C. dams D. cables
- A. protect B. hold C. keep D. maintain
- A. make B. force C. enforce D. encourage
