《辽史·本纪·卷十五》
二十日，萧合卓等进攻高丽兴化军未能攻克，班师回国。
乙卯，萧合卓等攻高丽兴化军不克，还师。
On the twentieth day, Xiao Hetuo and others attacked Xinghua Commandery in Goryeo, but failed to capture it and returned to their country.
<s>[INST] Kindly elucidate the central themes in this passage in English: 乙卯，萧合卓等攻高丽兴化军不克，还师。 [/INST] On the twentieth day, Xiao Hetuo and others attacked Xinghua Commandery in Goryeo, but failed to capture it and returned to their country.</s>
Kindly elucidate the central themes in this passage in English: 乙卯，萧合卓等攻高丽兴化军不克，还师。
user
On the twentieth day, Xiao Hetuo and others attacked Xinghua Commandery in Goryeo, but failed to capture it and returned to their country.
assistant