阅读下面文字,完成1-4题。科学认识沙尘暴沙尘暴可谓臭名昭著,特别是在20世纪最后几年,声讨它的声音越来越强,黄色的天空夹着泥土的春雨成为北方一景。沙尘暴真的那么讨厌吗?其实,在自然界,沙尘暴非但不是令人不快的“不速之客”,它还是带来丰富养料的“老朋友”和改善环境质量 Read the following text to complete 1-4 questions. Scientific knowledge of sandstorms Sandstorms are notorious, especially in the last few years of the twentieth century, which denounced it as more and more powerful. The yellow sky clinging to the earth’s spring rain has become a landscape in the north. In fact, sandstorms are not only unpleasant “uninvited guests” in nature, but they are also “old friends” who bring rich nutrients and improve the quality of the environment