第15题:[单项选择]<br><br><br/>A.Theirrelationshipswiththeprofessors.<br/>B.Theirfinancialaidpackages.<br/>C.Theirlightschoolload.<br/>D.Theirrichextracurricularactivities.<br/>参考答案:B 答案解析:[听力原文] What makes the students at Princeton University the happiest ones