《汉书·传·匈奴传下》
单于接受了投降的人，把他们安置在左谷蠡地方，派使者上书汉朝报告情况说： 我已全部接受下了。 
单于受置左谷蠡地，遣使上书言状曰： 臣谨已受。 
The Great Chanyu accepted the surrender and settled them in the Zuogu region and sent a messenger to the Han court with the message: "I have accepted the surrender of all of them."
<s>[INST] Kindly elucidate the central themes in this passage in English: 单于受置左谷蠡地，遣使上书言状曰： 臣谨已受。  [/INST] The Great Chanyu accepted the surrender and settled them in the Zuogu region and sent a messenger to the Han court with the message: "I have accepted the surrender of all of them."</s>
Kindly elucidate the central themes in this passage in English: 单于受置左谷蠡地，遣使上书言状曰： 臣谨已受。
user
The Great Chanyu accepted the surrender and settled them in the Zuogu region and sent a messenger to the Han court with the message: "I have accepted the surrender of all of them."
assistant