《汉书·纪·武帝纪》
夏季四月二十一日，立皇太子。
丁卯，立皇太子。
On the twenty-first day of the fourth month of summer, the crown prince was established.
<s>[INST] 请将下面的文言文翻译成英语: 丁卯，立皇太子。 [/INST] On the twenty-first day of the fourth month of summer, the crown prince was established.</s>
请将下面的文言文翻译成英语: 丁卯，立皇太子。
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On the twenty-first day of the fourth month of summer, the crown prince was established.
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