What does Lu You's poem describe on paper?

It describes that the knowledge gained from books is not perfect after all.

Lu You, the author of Reading on a Winter Night? Song dynasty

The ancients learned nothing, and it takes time to grow old.

What you get on paper is so shallow that you never know what you have to do.

Translation:

The ancients spared no effort in their studies, and often achieved nothing when they were old. After all, the knowledge gained from books is not perfect. If you want to understand the truth deeply, you must practice it yourself.

Creative background:

Reading Yu Zi on a Winter Night is a poem by Lu You, a poet in the Southern Song Dynasty. This poem was written by the poet Yu Qingyuan to his youngest son Lu Yu in Yin Shan in five years. In the silent night, the poet could not restrain his surging emotion, so he wrote this philosophical poem and gave it to his son Yu Zi with deep affection.

By describing Lu You's education to his son Yu Zi, the whole poem tells readers to have a tireless and persistent learning spirit. It contains the poet's ardent expectations for his children and also embodies the poet's profound educational thought. When the poet was young, he taught his son to cherish time, study hard, persevere, don't rush for success and don't study hard.