Looking up at the blue sky with your eyes thousands of miles away, you can’t help but think about it. In distant ancient times, our ancestors looked at the blue sky and wanted to use a method to dye white cloth into a beautiful color like the blue sky to make the clothes more beautiful. According to historical records, around the Neolithic Age, the working people of our country discovered a kind of blue grass with red flowers growing in the wild. If you pick one of its leaves and rub it in your hands, its yellow-green juice will stain your fingers and turn into a beautiful blue-green color in a moment. If the fabric is rubbed with its fresh leaves, the fabric will be dyed blue, so people have collected indigo grass for dyeing since then.

Later, people discovered that there were certain shortcomings in using this wild bluegrass to rub fabrics for dyeing, especially thin and soft fabrics such as silk, which could not withstand such rubbing. As a result, some people switched to warm water dipping method for dyeing. As early as 3,000 years ago, our ancestors had already used indigo grass for dyeing. When dyeing linen or other plant fibers, lime is also added to the dye liquor to increase its alkalinity, so that the dyeing effect of the fabric is better.

According to the records of "Zhou Li: Diguan Zhang Lancao", at that time, a man named Xun Kuang summarized the experience in printing and dyeing production technology and proposed that "green, taken from blue and green from blue" "Blue" is a philosophical saying. "Qing" means "green"; blue refers to the blue grass used to make indigo. Indigo is specially used to dye cyan, but the dyeing effect is far better than the original indigo. Xun Kuang used this vivid example from the practice of printing and dyeing production to illustrate his simple materialist thoughts and illustrate that everything in the world is always changing, developing and advancing.

Currently, we are embarking on a new Long March of "rejuvenating the country through science and education", and we need to draw the blueprint for the four modernizations. In the process of realizing the four modernizations, we must strive to climb new heights and quickly enter the era of scientific and technological information. Students surpass teachers, apprentices surpass masters, young people surpass old people, and descendants surpass predecessors. This is by no means a strange theory, but an inevitable law of historical development and a requirement of the times. Our country is a developing country, and science and technology and the national economy are still very backward. As long as we adhere to the party's line and principles and policies, and the whole country works together with one heart and one mind to pursue the four modernizations, we will catch up with and surpass the world's advanced level in the near future, and establish In the forest of the world. If the knowledge is shallow, as long as you think it is wrong and study diligently, you can transform into the opposite. If you are ignorant and ignorant, you still think that everything is prepared for you. This kind of greenness, although it is obtained from blue, will never be greener than blue.