阅读理解
If you travel by air across the center of Africa or South America, you will fly over forests for thousands of kilometers. These great forests are the oceans of trees. They are full of thousands and thousands of different kinds of plants.
However, the world's forests are getting smaller and smaller all the time. We are cutting down the trees. If we cut down our forests, a lot of plants and animals will disappear from the world in a lot of places. The new farmland will soon become desert. Crops will not grow there. It will not rain very often, and the climate will change, too. These will be dangerous for everyone in the world. That is why we must take care of our forests.