《后汉书·列传·南匈奴列传》
这年七月，单于上书说：臣世代蒙受朝廷恩德，无法计算。
其年七月，单于上言：臣累世蒙恩，不可胜数。
In July of this year, the Chanyu wrote a letter to the emperor, saying: Your servant has received the favor of the imperial court for generations, and cannot calculate the amount.