杵臼交

Explanation: Means excluding the poor and lowly friendship. 　　Source: "Han Wu Yu Chuan": "Shamu the public to tour the Imperial College, no MERITS, customer service is a variable commission, to woo Chung lease. Woo with words shocked, and then were scheduled to meet at Chujiu between." 　　Examples: Wendeng week students, and adult students were, brush less, then _set_ at ~. From poverty, so Zhongsui by weeks. ★ Qing Pu, "Strange Tales of immortality"