gǔ / rén / cháng / yòng / shuǐ / de / qīng / zhuó / lái / bǐ / yù / pǐn / xíng / de / hǎo / huài古人常用水的清浊来比喻品行的好坏。Ancient people often used the clarity and turbidity of water as a metaphor for moral character.