impure 托福专八

Impure drinking water is a cause of disease.

不洁饮用水是引发疾病一个原因。

An impure oxide of cobalt, used to produce a blue color in enamel and in the making of smalt.

蓝色颜料，主要由钴和锡氧化物组成。

The technological condition of Potassium Sulfate production from impure glaserite and impure Potassium chloride, is discussed in the paper,It is proved by experiment.

文章介绍了利用电解质溶液理论计算不纯净钾芒硝与不纯净氯化钾转化制取硫酸钾工艺条件，并通过试验加以验证。