With the increase in trade in both business contacts and trade relations strengthening mutual understanding and communication deepens, there is the trend of personal content into letters, which also contributed to the liberalization of its format.

With the increased operational linkages between trade and strengthening trade relations, mutual understanding and communication between in-depth, there is a growing trend of correspondence from infiltration personal content, and this also contributes to the liberalization of its format.

Along with trade both sides service relation increase with the trade ties enhancement, each other understanding and the communication is day by day thorough, has the person content permeating official letter tendency, this has also encouraged its form liberalization.

As trade increased business contacts and the strengthening of trade relations between the two sides, mutual understanding and communication among the growing, personal content into the official correspondence of the trend, which also contributed to the liberalization of its format.

With the enhancement of increase and trade relations of the business relations of both sides of the trade, understanding and communication between each other are deepened day by day, someone's content seeps into the trend of the official letter, this has encouraged the liberalization of its form too