Test Analysis: This question is based on China's poems and aphorisms. The topic points to "both of them contain the philosophy that quantitative change causes qualitative change". In option A, "It is difficult to wash off all the sand, but start with gold", which means that gold must be filtered thousands of times. Although it is difficult, only when all the sand is washed away will the shining gold be revealed. "Perseverance, stone can be carved" means that even metal jade can be carved with a knife. The extended meaning is: as long as you make unremitting efforts, no matter how difficult it is, you can do it. Both of them contain the philosophy that quantitative change leads to qualitative change, and A conforms to the meaning of the question. The two sentences in option B reflect people's consciousness and mood, but they do not reflect the philosophy that quantitative change causes qualitative change. The first sentence in the C option means that the article is a career that has been passed down through the ages. The ups and downs are only known by the author, and do not reflect the qualitative changes brought about by quantitative changes. The D option "Flowers are more and more colorful, shallow grass can have no horseshoe" reflects the need to see the essence through the phenomenon.