Sales of mechanical equipment; Sales of machinery parts and components; Sales of building materials; Sales of special machinery for tunnel construction; Sales of machinery for construction engineering; Sales of mining machinery; Sales of daily necessities; Technical services, technical development, technical consulting, technical exchange, technology transfer, and technical promotion; Import and export of goods. (Except for projects that must be approved in accordance with the law, the enterprise may independently carry out business activities in accordance with the law with a business license. )