中文摘要：

根据现任职位、任职经历和任职知识3个维度将董事会成员分为咨询董事和监督董事,利用中国1 868家A股上市公司数据,实证检验了这两类董事对董事会咨询绩效和监督绩效的影响.研究发现：1）咨询董事数量与董事会咨询绩效正相关,公司特有知识、公司咨询需求和CEO接受咨询意愿有正向调节作用;2）咨询董事数量的增加不会削弱董事会的监督绩效;3）监督董事数量与董事会监督绩效正相关,但对董事会咨询绩效产生一定负面影响.研究结论对于提高董事会治理有效性具有重要的理论价值和实践意义.

英文摘要：

In this paper, we focus on public-private partnership projects whose revenue depends on charges collected from users. We investigate whether the government should extend the private sector＇ s operation peri- od when the demand unexpectedly declines so that Pareto-improvement can be achieved for both the private sector and consumers. Our results show that （ 1 ） in some scenarios the Pareto-improvement can be achieved by solely dropping price without need for an extension of the operation period; （2） when an extension is nee- ded to realize the Pareto-improvement, the added period depends on the operation costs and renegotiation costs of the government and the private sector, respectively. Our study intends to provide theoretical support for the government when making operation period extension decisions.