我看楼主对有些答复很无奈，我很理解。我的答复完全杜绝机译，改写过程中语法保证准确，请审阅。
As we know industrialization began in the 18th century, since then new sales and distribution channels were required thereby affecting the trade fair business. During the 18th and 19th centuries, fairs became the site displaying a variety of available goods instead of the sites for direct sales, in such kind of fairs only samples of much more diverse product ranges were exhibited. These fairs were called Sample Fairs (from the German "Mustermesse"). The first exhibition site for a sample fair was in Leipzig in 1895. Untill the middle of the 20th century these sample fairs dominated the fair scene in Europe. In addition, at the end of the 19th century, and in the early decades of the 20th century, several exhibitions of national significance were organized, most of them were dedicated to a specific theme such as electricity, health, mechanical engineering, and they primarily oriented to the general public.
After World War II, with the rising specialization of the economy a large amount of specialized fairs and a broader diversity of fair locations arose. Although high-speed, electronic communications technology had rapid progress during the 20th century; fairs today are still considered as one of the most dynamic and effective sales and marketing tools in existence. Entering the 21st century, the fair business features an increasing supply of fairs and exhibitions: the activity field of fair organizers has been expanded into the worldwide level through international co-operations.
It is well known that a lot of new and large exhibition sites have been built or are under construction in China, Korea, Singapore and the Near East, beecause these countries place their expectations of economic growth and prosperity on the exhibition industry. Some Asian organizers start to hold their own exhibitions in Europe or co-operate with worldwide acting exhibition organizers.
Trade fairs are market events with a specific duration and held regularly. In the trade fairs, a large number of companies present their main products and mainly sell it on the basis of samples. And trade and business men are their main visitors. On the contrary in the exhibitions, a large number of companies present a representative product and sell it or provide information about it just for promoting sales. And the general public is their main visitors.
问题补充：还有一段 As a criteria for an international trade fair and exhibition, the number of participating foreign exhibitors must reach at least 10% of the total number of exhibitors, or the number of foreign visitors must account for at least 5% of the total number of visitors.
In addition to international fairs and exhibitions, there are also national or regional ones. The visitors of For national trade fairs and exhibitions the visitors may come from areas extending beyond a given region, while for regional trade fairs and exhibitions the visitors may come from a specific province or county.
