According to whether knowledge can be clearly expressed and effectively transferred, knowledge can be divided into explicit knowledge and tacit knowledge. Explicit knowledge can be used by humans with a certain code system (most typical is language, also. Including teaching formulas, Various types of symbols, such as diagrams, braille, sign language, semaphore, etc. ) are fully expressed. Tacit knowledge refers to subjective knowledge that is not easy to express in words, languages, images, etc. Existence, impressions, know-how, organizational culture, customs, etc. exist. According to the above definition, what belongs to explicit knowledge is:. ['The apprentice finally learned the emblem carving technique of the national master craftsman through observation, imitation and personal practice.', 'Xiaoshi learns cooking in the chef class. The teacher repeatedly emphasizes the heat. He tried his best to notice that Lai was still not good enough.', "c. When Xiao Xiagang graduated from a foreign language education major as a foreign language teacher, she always couldn't control the bathhouse well.", 'Xiaohong memorizes 10 foreign language words every day. After half a year, she can finish reading a short story in a foreign language.']