China news service, September 9, 2008. Yesterday, sandstorms hit Dunhuang, Guazhou and Yumen. When the sandstorm was the worst, the visibility in some areas was only 400 meters, which was the lowest.

(l) From left to right, from top to bottom are A, D, G, C, E, F and B respectively.

(2) Arid and semi-arid areas

(3) The frequency is faster and the interval is shorter.

(4) Because the northern part of China is located to the east of the Asian high, the northwest monsoon prevails in winter and spring.

(5) Natural causes: abnormal climate, rising temperature, intensified evaporation and serious land desertification. Man-made reasons: excessive land reclamation and overgrazing in the northern grassland lead to grassland degradation and desertification, and excessive logging in forest areas leads to serious soil erosion; There are many construction sites, and the sand used in construction site lacks protection.

(6)C

Taking sandstorm as the breakthrough point, this topic comprehensively investigates the causes of desertification in northwest China and students' comprehensive analysis ability. As can be seen from the figure, the dusty weather is mainly distributed in the northwest of China. As can be seen from the figure, the northwest is far from the sea, the mountains are blocked and the climate is dry. Question (L), such questions should be answered according to the context. Question (2), the area where sandstorms occur belongs to arid and semi-arid areas in China. Question (3), examine students' ability to obtain and interpret information from pictures. As can be seen from the figure, the occurrence trend of sandstorms in China is to accelerate the frequency and shorten the interval. Question (4), the reason why the sandstorm path in China is northwest-southeast is that the northern part of China is located to the east of the Asian high, and the northwest monsoon prevails in winter and spring. Question (5) should be analyzed from two aspects: natural causes and human causes. Question (6), adjust measures to local conditions, take effective targeted measures, reduce planting, and moderately develop animal husbandry.