Sandstorms blow 300,000 tons of dust into Beijing. The severe sandstorm that was hovering

over Beijing for the past few days finally moved out of the city yesterday morning, leaving a heavy layer of dust and sand on the ground. Experts with the State Environmental Protection Administration said some 30,000 tons of fine sand and dust were blown into the capital. In an earlier sandstorm last weekend, some 26,000 tons of sand and dust also landed on Beijing.

Dong Xuhui, director of the sandstorm research group under the administration, said the sandstorm that invaded Beijing this week was the most severe since the group began conduction sandstorm research in 1995. "In some sandstorms in the Inner Mongolia Autonomous Region, visibility had been lowered to less than 1 meter," Dong said.

The administration's satellite sandstorm supervision system showed that sand and dust drifted at about 2,500 to 3,500 meters above the ground, affecting Beijing for 51 consecutive hours. "The sand and dust particles in the air are relatively small, so they could easily invade people's breathing systems." Dong said, "So it is better to stay indoor in such weather."

Unfortunately, there are no effective ways to stop or decrease the frequency of sandstorms in the near future. Gao Jixi, a researcher with the China Environmental Science Institute, suggested that the government address that the overall problem as part of its environmental protection policy.

Though protective forests in North China are expected to grow soon, Gao said that drifting sands at high altitudes could still invade most cities. "We should consider the environment in northern and western China as a whole when adopting related environmental protection policies," Gao suggested.

He said governments in the relevant provinces and autonomous regions should speed up their industrial restructuring and firmly put a stop to industrial practices that harm the environment. Gao said some hasty tree planting activities should also be stopped because many of tree species have now been found not to match the local soil. "Planting more trees does not mean the improvement of the environment," he said.

Gao was invited to present an environmental report to premier Zhu last year. Gao had advocated the building of a large ecological system in northern and western China to resist sandstorm.

He objected to environmental stress caused by humans interfering with nature. "We should respect nature's rules by restoring the original ecological systems in those regions." Gao said. Following that principle would be the best way to fight sandstorms, he added.

What's the main idea of this article？

A．Sandstorms blow 300,000 tons of dust into Beijing.

B．Sandstorms are threatening human's life.

C．There is no effective way to stop sandstorms in the near future.

D．B and C.