更困难的问题是我们是否能够准确预测认知和记忆能力正常人士的阿尔茨海默症，或在阿尔茨海默症出现五年前就做出预测。
The trickier question is whether we will be able to predict Alzheimer’s disease accurately in those with normal cognition and memory, or to predict it more than five years in advance.