it’s come from 观书有感二首 It’s writer is “zhuxi”(朱熹) He came from Song dynasty . the title is means he has some thought when reading books
半亩方塘一鉴开，
The square pond with half an acre size looks like a mirror, it's clean and bright.
天光云影共徘徊。
The shine of the sky and the shadow of the clouds are reflected in the pond, they are swinging and full of energy.
问渠那得清如许，
If you wonder why the spring is so clear,
为有源头活水来。
it is because the source is continuously supplying living water.
