Losing your ability to think and remember is prett...

Losing your ability to think and remember is prettyscary. We know the risk of dementia (痴呆症) increases with age. But if you have memory slips, you probably needn't worry. There are pretty clear differences between signs of dementia andage-related memory loss. After age 50, it's quite common to have trouble remembering the names of people, places andthings quickly, says Dr. Kirk Daffner of Brigham and Women's Hospital in Boston. The brain ages just like the rest of the body. Certain parts shrink, especially areas in the brainthat are important to learning, memory and planning. Changes in brain cells can affectcommunication between different regions of the brain. And blood flow can be reduced asblood vessels narrow. Forgetting the name of an actor in a favorite movie, for example, is nothing to worry about. Butif you forget the plot of the movie or don't remember even seeing it, that's far moreconcerning, Daffner says. When you forget entire experiences, he says, that's "a red flag that something more seriousmay be involved." Forgetting how to operate a familiar object like a microwave oven, orforgetting how to drive to the house of a friend you've visited many times before can also besigns of something going wrong. But even then, Daffner says, people shouldn't panic. There are many things that can causeconfusion and memory loss, including health problems like temporary stoppage of breathingduring sleep, high blood pressure, or depression, as well as medications (药物) likeantidepressants. You don't have to figure this out on your own. Daffner suggests going to your doctor to checkon medications, health problems and other issues that could be affecting memory. And the bestdefense against memory loss is to try to prevent it by building up your brain's cognitive (认知的) reserve, Daffner says. "Read books, go to movies, take on new hobbies or activities that force one to think in novelways," he says. In other words, keep your brain busy and working. And also get physicallyactive, because exercise is a known brain booster.Why does the author say that one needn't be concerned about memory slips？ 1..Why does the author say that one needn't be concerned about memory slips？()

A、Not all of them are symptoms of dementia.

B、They occur only among certain groups of people.

C、Not all of them are related to one's age.

D、They are quite common among fifty-year-olds.