《后汉书·列传·方术列传上》
并问 ：你怎么知道的？ 
问何以知之。
And asked: "How did you know?"
<s>[INST] Kindly elucidate the central themes in this passage in English: 问何以知之。 [/INST] And asked: "How did you know?"</s>
Kindly elucidate the central themes in this passage in English: 问何以知之。
user
And asked: "How did you know?"
assistant