zhè / wèi / lǎo / xiào / zhǎng / jǐ / shí / nián / rú / yī / rì / gān / dāng / jiào / yù / shì / yè / de / rú / zǐ / niú

这位老校长几十年如一日，甘当教育事业的孺子牛。

For decades, this retired principal has willingly devoted himself to education.