A,这个题考查的是虚拟语气,had sb done...,sb would have done=if sb had done,sb would have done.这个是对过去的动作的虚拟,用过去完成时,表示如果某人做过某事,那么某人就会.
这个句子就等于If she had tried harder in the past few months,Cherry would have passed the entrance exam.
翻译：如果Cherry在过去的几个月里学的再努力些,她就会通过考试的.