VOA慢速英语:研究表明许多人可能不了解他们患痴呆症的风险

challenging – adj. difficult in a way that is usually interesting or enjoyable

crossword puzzle – n. a puzzle in which words that are the answers to clues are written into a pattern of numbered squares that go across and down

geriatric – adj. of or relating to the process of growing old and the medical care of old people; of or relating to geriatrics

regular – adj. happening over and over again at the same time or in the same way : occurring every day, week, month, etc.

supplement – n. something that is added to something else in order to make it complete