Because these two industries are very common, in the early days of opening up, a large number of people engaged in these two industries, the technical content is not high. They are also labor-intensive industries, which often recruit a large number of people, unlike the former foreign trade companies and senior secretaries in offices, which make people suspicious, so that the deceived people will not be so anxious when they first enter a collective group, and provide valuable brainwashing time for MLM groups.