The last time China’s top leader, Xi Jinping, traveled to North Korea, that country’s dictator, Kim Jong-un, was reeling from sanctions and failed nuclear talks with the United States. 上一次中国最高领导人习近平访问朝鲜时，朝鲜的独裁者金正恩正深陷制裁困境，与美国的核谈判也以失败告终。 Now, nearly seven years…