《观书有感》是宋代学问家朱熹的作品。本诗借助池塘水清因有活水注入的现象，比喻要不断接受新事物，才能保持思想的活跃与进步。

《观书有感》 朱熹

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。

The Book
Zhu Xi

There lies a glassy oblong pool,
Where light and shade pursue their course.
How could it be so clear and cool?
For fresh water comes from the source.