阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Beijing and large areas of northern China woke to 【小题1】 (choke) sand and dust, as a winter sandstorm sent many of the air pollution 【小题2】 (level) off the charts.

The sandstorm originated in Mongolia and 【小题3】 (gradual) moved south, covering much of northern China, from the eastern city of Tianjin to Xinjiang region in the far west. The sandstorm is expected 【小题4】 (last) for two days.

In the spring of 2021, Beijing was hit by the biggest sandstorm in nearly a decade, 【小题5】 turned the skies a shade of orange. In previous decades, each May 【小题6】 (see) at least two rounds of sandstorms. The 【小题7】 (frequent) and severity of sandstorms was partly due to drought, growing population pressure and poor progress in revegetation (再种植), which caused rapid desertification of land in the north and northwest. But sandstorms 【小题8】 (decrease) sharply ever since. The annual number of sandstorm-affected days in Beijing fell 【小题9】 a peak of 26 days in the 1950s to just three days after 2010.

Since 2000, the Chinese government has spent billions of dollars on sandstorm prevention, started 【小题10】 (vary) reforestation and ecological projects and sent up satellites to monitor sandstorms and alert weather agencies ahead of time.