有很多沙粒是红色的，这是由于其表面有一层薄薄的铁，这些铁元素来自于空气中。
Many desert sands have a faint red color caused by a thin layer of iron that precipitates from the atmosphere and coats the grains. (Magnification 85x)
牡蛎会尽职尽忠地为自己腹中的小珠子包裹上一层又一层的珍珠质。 比起那些要从小沙粒开始慢慢成长的珍珠，人工的方法明显会节省很多时间。
The oyster dutifully coats the little marble with anouter layer of pearl and much time is saved not having to grow each pearl upfrom the size of a sand grain.
18世纪20年代，军事飞行员驾驶着载满带电沙粒的飞机去袭击云层，尝试人工造雨并且清除雾层。
In the 1920s airplanes loaded with electrified sand were piloted by military aviators who "attacked" the clouds in futile attempts to both make rain and clear fog.
18世纪20年代，军事飞行员驾驶着载满带电沙粒的飞机去袭击云层，尝试人工造雨并且清除雾层。
In the 1920s airplanes loaded with electrified sand were piloted by military aviators who "attacked" the clouds in futile attempts to both make rain and clear fog.
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