[chéng qīng]

The water of the lake is green and clear.
湖水碧綠澄清。

clarify some facts
澄清事實

clear up a misunderstanding
澄清誤會

demand clarification
要求澄清

clear up ambiguity [obscurity]
澄清模棱兩可之處

The President's statement cleared the air of rumours and guessing.
總統的聲明澄清了種種謠傳和猜測。

bring peace and order to the country
澄清天下

[dèng qīng]

Alum will settle turbid water.
明礬可以澄清濁水。