单项选择题
老化是机体结构和功能上的微小变化长期积累的结果，表明老化的哪种特征：
单项选择题 从自然、社会文化和人际关系等多方面、多角度、多层次考虑和解决问题，是遵循了哪项维护和促进老年人心理健康的原则：
单项选择题 He said he had ________ the performanceof the new model and was surprised at what he had seen then.
单项选择题 This old school is still having ________of students ________ it had a hundred years ago when it was first founded.
