Was the source of the sentence really San Mao's original words? What if it came from a book or a speech? He needed to confirm if this was San Mao's original words. If one could find the source of this sentence by searching San Mao's life, works, and remarks, then they would be able to find the source of this sentence. If this sentence was not San Mao's original words, then he needed to further confirm the source of this sentence. If it was something else, he could search for the source of this sentence by searching for the novel, works, and comments. If you can't determine the origin of this sentence, you can try to contact the author or publishing platform of the work to obtain more accurate information.