天渊之隔

Explanation: Deep: deep pools. Described as very far apart, very different. 　　Source: Ming Feng Meng, "Awaken the common saying," xxxv: "That's Xu Yan, Xu Zhao, while also earning from an estate, than the Yan, still a world of separated red neck all day long jealous." 　　Examples: Zhao Gongzi heard of his big expensive phase, state and virtue are all, Talents of malpractice, as good than Hangong Zi ~. ★ Qing Wu Xuan, "Biography of the dragon," sixty-back