That's at least partly because memories change over time.

这至少在一定程度上是因为记忆会随着时间而改变。

Researchers found around 300 inactive older adults with memory changes called mild cognitive impairment (MCI) .

研究人员发现，大约 300 名不活动的老年人的记忆力发生了变化，即患有轻度认知障碍。

Some memory changes are normal, but most memories should remain intact.

一些记忆变化是正常的，但大多数记忆应该保持完整。

It's a fascinating research area why--about memory changes early on.

这是一个令人着迷的研究领域——关于记忆早期的变化。

Researchers hope the study will not only help understanding of cognitive ability and memory changes in dogs but also in the human aging process.

研究人员希望这项研究不仅有助于了解狗的认知能力和记忆变化，而且有助于研究人类的衰老过程。