大单小单大双小双

简介：The north gate of Yuezhou is only four miles away from the bank of the Yangtze River. Within these four miles, the government troops dug numerous trenches and built several forts to support water warfare in the river - if the bandits could invade these trenches , destroy the forts and cut off the support of the Yuezhou defenders to the navy, then the victory of the rogue navy will be twice the result with half the effort.