中文摘要：

民间借贷中的逆向选择和道德风险的发生与借贷双方的信息不对称性密切关联。在熟人社会中，民间借贷和信息传播都依靠着以血缘、亲缘等强关系为主的社会关系网络，两者的路径一致有效降低了信息不对称性造成的民间借贷风险。在公民社会中，民间借贷依托于市场规则，信息传播依托于公共平台，两者通过公开化、市场化的操作有机统一起来，从而大大降低了信息不对称性造成的民间借贷风险。在熟人社会向公民社会的转型过程中，民间借贷关系的多样性和信息传播渠道的局限性容易造成两者的不相匹配，逆向选择和道德风险行为的违法成本低，从而使得正常的民间借贷容易异化为非法集资或金融诈骗。现实的民间借贷纠纷案例展示了民间借贷危机发生的微观机理。

英文摘要：

The occurrence of adverse selection and moral hazard is closely related to the information asymmetry in private lending. In acquaintance society, both the private lending network and the information network are composed of strong relations such as blood relatives, the coupling of which effectively reduces the private lending risk resulting from the information asymmetry. In civil society, the occurrence of private lending depends on the market rules and the dissemination of information depends on public platform. They are coupled by transparent rules and regulations, which leads to a decrease in the private lending risk resulting from the information asymmetry. During the transition period from acquaintance society to civil society, the limited information transmission channel does not match the diversified private lending relationships. The low illegal cost leads to the alienation of private lending. Aprivate lending dispute case shows the micro-mechanism of the private lending crisis.