B．it is good to get rid of the grass in the deserts

　　C．all places without much rain will become deserts

　　D．it is better to grow crops on dry land than to grow grass

　　解析：推理判断题。由文章可知，植被对控制土地沙漠化起主要的作用，A项正确。其他三个选项不符合文意。

　　B

　　Organic(有机的)farming is a type of agriculture that benefits from the recycling and use of natural products. Use of dried plants not only saves money，but also ensures the growth of crops.The technique is characterized by the use of green manure(肥料)，biological pest control methods and special farming techniques to keep soil productivity. Limiting the use of man－made chemicals or completely doing away with them reduces the risk of diseases. Today，organic farming is a major and preferred industry around the world. Organically grown food products have a huge market，with farmlands covering about 10% of the total world－farmland cover. The hard work of Sir Albert Howard， the Father of Organic Farming， has paid off.

　　Advantages of Organic Farming：

　　(1) The economics of organic farming are characterized by increasing profits through reduced water use and reduced soil erosion(侵蚀).

　　(2) Organic farming produces the same crops as those produced through traditional farming methods，but uses half the energy，and holds 40% more topsoil.

　　(3) Farming the organic way enables farmers to get rid of weeds without the use of any chemicals.

　　(4)The use of green pesticides(杀虫剂) is environmentally friendly and does no harm to human's health.

　　Disadvantages of Organic Farming：

　　(1) Organic methods of farming produce less，compared to traditional farming techniques.

　　(2) Organic agriculture does little to fight global climate change. Though organic farming practices are recognized as giving out less CO2，but not to a significant degree.

　　However，though there are some disadvantages of organic farming，farms where organic methods for cropping have been used have more advantages than traditional farms. Organic agriculture is surely better in the long term

　　24．The underlined sentence in Paragraph 1 shows that Sir Albert Howard __B__.

　　A．worked hard for nothing

　　B．succeeded in organic farming

C．spent all his time on organic farming