广播电视英语短句 第 95 课：陶瓷净水器-4

It could be sawdust or agricultural waste like grain hulls, cocoa or coffee shells. Pine needles can also be used. 这个材料可以是锯末，或者是农业废材，像是谷壳、可可或者咖啡豆壳，也可以使用松针。

The mixture is shaped into a cone and then fired. 混合好的材料被塑成圆锥体后进行烧制。

Burning away the material added to the clay leaves tiny holes. 将混合在粘土中的那些易燃材料烧掉，这样能够留下许多细微的小孔。

These holes let water slowly pass through the walls of the filter. 这些细孔能够让水缓慢的流过过滤器。

A protective coating of colloidal silver is painted on the inside and outside of the filter to kill bacteria. 在过滤器的内外壁涂上一层胶态微粒银保护膜来杀死细菌。