6.citizens suspected of harbouring impure thoughts.
被疑有不道德思想的公民。
7.Impure drinking water is a cause of disease.
不洁的饮用水是引发疾病的一个原因。
8.The technological condition of Potassium Sulfate production from impure glaserite and impure Potassium chloride, is discussed in the paper,It is proved by experiment.