题目内容：

    Maybe you pop vitamins supporting brainpower, or stock upon these foods that boost brain health. But new guidelines from the American Academy of Neurology suggest there's something better you can do to keep your mind sharp.

A quarter of adults aged 80 to 84 experience mild cognitive (认知的) impairment, according to AAN. To address the widespread problem, a group of neurologists and Alzheimer's (阿尔兹海默氏症的) specialists went through existing studies to define the best ways to prevent and treat cognitive decline-and you might be surprised by what they included and what they didn't.

Surprisingly, the AAN guidelines don't include any medication (药物) or dietary recommendations. The authors stress that there haven't been any high-quality, long-term studies finding foods or medication can help cognitive decline. The guidelines also say doctors can consider suggesting cognitive training to patients with memory loss but not to rely on it. So far, the report's authors say the evidence is too inconclusive to say for sure if brain exercises, like memory and attention training or problem solving for everyday issues associated with memory loss, are beneficial. Still, these morning brain exercises can't do any harm.

But there was one big discovery from the new guidelines: Exercising just twice a week could improve cognitive decline. One study showed adults with mild cognitive impairment who did resistance training twice a week scored better on executive function and associative (联想的) memory tests than a group that worked on balancing, stretching, and relaxing.

What's more, another study had older adults attend either biweekly health classes or sessions of aerobics, strength training, balance exercises, and multitasking training. Six months later, the ones who'd exercised regularly scored better on cognitive health and memory tests, plus had less brain shrinkage.

AAN now recommends doctors tell patients with memory loss to exercise twice a week to keep their minds sharp. This is the best time to exercise if you want to improve your memory. It looks like you've got just one more reason to clear time in your schedule for a workout — even if it's only on the weekends.

1.What does the underlined word ''impairment'' in paragraph 2 refer to?

A.Error. B.Decline. C.Development. D.Presence.

2.AAN may be uncertain about       .

A.strength training B.resistance training

C.exercises twice a week D.brain exercise

3.Which of the following may the author agree with?

A.Daily exercises are beneficial to Alzheimer.

B.The AAN guidelines attach importance to workout.

C.Medication is of significance in the AAN guidelines.

D.Stocking up on vitamins supporting brainpower means nothing.

4.In which section of a newspaper may this text appear?

A.Exercise. B.Entertainment. C.Science D.Health