Chapter One, the MainExchange Channels Between South and North.
第一章，南北朝交流的主要渠道。
2
The trades of construction market include mainexchange and affiliate exchange, the first is objective exchange, the second is information exchange.
建筑市场交易包括主交易和从交易两种行为，主交易是实物交易，从交易是信息交易。
3
The congenital advantage of the language makes the language become peoples mainexchange way, the need of keeping a record of events hastens the birth of the picture.