单选题 If the old are left to do as much as they can for themselves, ______.

【正确答案】 D
【答案解析】[注释] 本题依据在第二段首句,关键词语是…the same means of keeping their minds and muscles active,意思是“老年人跟孩子一样需要自己多做些事情来保持头脑和肌肉的活力”。