《旧唐书·本纪·卷四》
十八日，命令两年确定一次户数。
已未，敕二年一定户。
On the 18th, he ordered household registrations to be conducted once every two years.
<s>[INST] Convert the following modern Chinese text into Classical Chinese: 十八日，命令两年确定一次户数。 [/INST] 已未，敕二年一定户。</s>
Convert the following modern Chinese text into Classical Chinese: 十八日，命令两年确定一次户数。
user
已未，敕二年一定户。
assistant