dí jūn / chéng qiáng / jiān gù / wǒ jūn / jiǔ gōng bù xià / zhǐ hǎo / chè tuì

敌军城墙坚固，我军久攻不下，只好撤退。

The enemy's city walls were strong, and our army attacked for a long time without success, so we had to retreat.