Tā de xuéwèn rìxīn-yuèyì, zhēnshì wèn qú nǎ dé qīng rú xǔ, wèi yǒu yuántóu huóshuǐ lái.
His learning renews itself daily - truly 'ask the pond how it stays so clear? - because fresh spring water flows in.'
Tips
history
From Zhu Xi's 《观书有感》 (Song dynasty): 半亩方塘一鉴开，天光云影共徘徊。问渠那得清如许？为有源头活水来。 Written by the great Neo-Confucian philosopher on reading - books are the 'source-spring' that keep the mind clear. 源头活水 became a standard metaphor for continuous intellectual renewal.
usage
渠 here is classical for 'it' (referring to the pond), not 'canal'. 那 is read nǎ (= 哪, how). Always quoted with 为有源头活水来.
