阅读理解。 Trees are useful to men in three important ways: They provide them with wood and other products (产品), they give them shade (树荫), and they help to pr drought and floods. Unfortunately, in many parts of the world, men have not realized that the third of these services is the most important. In their eagerness (渴望) to make money from trees, some people have cut trees down in large numbers, only to find that without them they have lost the best friends they had. And besides (此外), they are usually too careless to plant and look after new trees, so the forests slowly disappear. This doesn't only mean that men will have fewer trees. The results are even more serious: where there are trees, their roots (根) break up soil-allowing the rain to sink in and also bind (固定) the soil, thus (因而) pring it from being washed away easily, but where there are no trees, the rain falls carrying away the rich top-soil. When all the top-soil is gone, nothing remains (剩下) but worthless desert. 1. Land becomes desert after all trees arte cut down, because ____. [     ] A. there is too much rain B. there are no more trees to keep the rich top-soil from being carried away by floods C. there is a strong wind D. roots of trees break up the soil 2. People cut down many trees because ____. [     ] A. they wanted to get wood from them B. they wanted to get money from them C. they didn't realize the importance of them D. all the above 3. Which of the following is NOT true? [     ] A. Tree roots can make the top-soil rich and the ground hard. B. Trees can make the rain sink into the ground. C. Trees can pr drought and floods. D. Tree roots can take away the top-soil