《资治通鉴·汉纪·汉纪十一》
匈奴右贤王认为汉军距自己路途遥远，不可能到达，经常饮酒而醉，毫不戒备。
右贤王以为汉兵远，不能至，饮酒，醉。
The Xiongnu Right Wise King thought that the Han army was far away from him and could not reach him, so he often drank and got drunk and was not prepared at all.