Nature is the greatest book, Goethe said, and in every page of his sentences we read the deepest news. And the words in this book are known to all; Alpas and Wulaofeng, Xuexili and Putuo, Laiyin River and Yangtze River, Limenghu Lake and Xizi Lake, Jianlan and Qionghua, Reed Snow in Xixi of Hangzhou and Red Tide of Sunset in Weini City, Lark and Nightingale, not to mention yellow barley, Wisteria, and green grass grow on the earth, fluctuate in the breeze. The symbols they use are always the same. Their meaning is always obvious. As long as you have no scars in your heart, no blindness in your eyes, no ears blocked, this invisible higher education will always be your place, and this most precious supplement without charge will always be available to you. As long as you know this book, you will not be lonely when you are lonely in the world, and you will not be lonely when you are poor. Poverty, distress and comfort, frustration and encouragement, weakness and supervision, loss and Nan Needle - Xu Zhimo