sentences:  The Sui army eventually advanced to about 20 km from Pyeongyang, the capital of Goguryeo.However, realizing the advanced hunger and exhaustion of his troops, and perceiving the formidable fortifications of Pyeongyang, Yu Zhongwen realised the looming impossibility of continuing the campaign.To taunt Yu Zhongwen, Eulji wrote the poem in sarcasm and sent it to the enemy general.