Four-letter idioms about learning:

Hanging a beam and stabbing the stock? The first time I saw you, I was in the middle of something. The most important thing to remember is that you have to be able to learn from your mistakes. To learn from the past?

Hanging beams and stabbing stocks [xuán liáng cì gǔ]: describing hard study

(sentence): having a heart to study but not the spirit of hanging beams and stabbing stocks.

凿壁借光[záo bì jiè guāng]: describes a person who is poor but studies hard.

(sentence): In ancient times, Kuang Heng, who chiseled the wall and borrowed light, became a great scholar of his generation; Wang Coronet, who learned to paint on the back of a cow, ended up in the fragrance of lotus flowers.

Zī zī bù juàn (zī zī bù juàn): refers to being diligent and tireless in work or study.

(Make a sentence): In order to improve the level of teaching, teachers tirelessly study their business.

秉烛达旦[bǐng zhú dá dàn]: literally meaning to stay up until morning with a candle lit, comparing to a person working hard until the next morning.

(Make a sentence): Mr. Li always corrects students' homework by candlelight.

Dǔ xué hào gǔ (笃学好古): means to study ancient books with great concentration.

(sentence construction): Duxue xué hào gǔ ("笃学好古"): In Liaodong, Yuan often gave lectures in the mountains and rocks, and was well known to the scholars for his admiration.

Niú jiǎo guà shū (牛角挂书): a metaphor for diligent study.

(sentence): I heard people say that when King Wei was young, he hung a book on his ox horn, and was very learned.

Náng yíng yìng xuě (囊萤映雪): describes hard study.

(sentence): The ancient spirit of learning is worth learning.