A、Continued rainfalls. B、The increase of carbon dioxide. C、The disappearance of grasslands. D、Less land for cows and sheep. B在谈到

Forests are of great importance to our environment because they can absorb carbon dioxide and produce oxygen. They may also provide shelter and food for many different types of plants and animals. Trees are cut down for many reasons but the main reasons are to make space to build new houses and to clear land to grow grass for cows and sheep to eat, to produce dairy foods. The trees being cut down are sold and are made into paper and furniture.
    Cutting down trees may have serious effects to the environment. (33)If animals’ homes, which are built in and around the trees, are destroyed, many species in the world will become extinct. For example, many different types of animals in South America had disappeared before scientists could learn about them. Cutting down trees also affects the climate. When rain falls on a forest, new clouds will be created. If huge areas of trees are cut down, clouds can not form, rain does not fall and the land becomes drier and drier and finally becomes deserts. (34)And what’s more, the carbon dioxide builds up and adds to the global warming which is making the earth become hotter and hotter.
    (35)In recent years, to protect the forests, many European countries are planting trees faster than they are cutting them down. Many trees were planted a few years ago to replace woodland and to create forests in areas where there wasn’t much wood. We can also help to save forests by reusing and recycling paper.