GRE Reading Comprehension: OG/PP2-GRE阅读OG/PP2 - P85O2438L3L449I1L

A person who agrees to serve as mediator between two warring factions at the request of both abandons by so agreeing the right to take sides later. To take sides at a later point would be to suggest that the earlier presumptive impartiality was a sham.