Arid regions cober arid and semiarid areas. 旱區包括乾旱區和半乾旱區。
Desertification is a process caused by the conflict between the low productivity of the arid land and the ever increasing material and social demand of human beings. 沙漠化是由於乾旱半乾旱區土地很低的生產力與人民群眾日益增長的物質文化需要不相適應造成的。