premise: The total turnover of China's exhibition industry has been growing at an annual rate of about 20 percent for years, said Vice Minister of Commerce Jiang Zengwei here on Monday.
  Jiang made the remark at the second seminar on China's exhibition economy. China has become an important country in Asia in size of exhibition industry, and will gradually become a regional "exhibition center" in Asia, said he.
  China now has over 160 large-sized exhibition halls with exhibition area of 2.8 million square meters, according to Jiang.
  Every year, China holds about 3,000 exhibitions of different types at home, and 800 exhibitions overseas, attracting participation of 5 million enterprises and 20 million visitors, he said.
  Some nation-level exhibitions, such as the China Export Commodities Fair in Guangzhou, High-technology Trade Fair in Shenzhen and Investment and Trade Fair in Xiamen, have become well-known and influential exhibitions in the world, he said.
   What are the nation-level exhibitions that have become well known and influential in the world?
hypothesis: China Export Commodities Fair in Guangzhou