题目内容：

Directions: Read the passage carefully. Fill in each blank with a proper sentence given in the box. Each sentence can be used only once. Note that there are two more sentences than you need.

Slower Walkers Have Slower Minds, Scientists Reveal

Of all human activities, few are so readily credited with enhancing the power of the mind as going for a good walk. However, those who assume that strolling along at a gentle pace is the symbol of superior intellect should think again, scientists have said. 1.

Doctors have long used walking speed to gain a quick and reliable understanding of older peopled mental capability, as it is increasingly recognized that pace is associated with not only muscular strength but also the central nervous system. 2. The relationship was so obvious, however, that the US scientists now say walking tests could be used to provide an early indication of dementia（痴呆）.

Published in the Journal of the American Medical Association, the study revealed an average difference of 16 IQ points between the slowest and the fastest walkers at the age of 45, This reflected both the participants’ natural walking speed and the pace they achieved when asked lo walk as fast as they could. 3. Actually, slower walkers were shown to have “speeded aging'' on a 19-measure scale devised by researchers, and their lungs, teeth and immune systems tended to be in worse shape than the people who walked faster.

The 904 New Zealand men and women who were tested at 45 were tracked from the age of three, each undergoing multiple tests over the years. The long-term data collection enabled researchers to establish that kids with lower IQ scores, lower linguistic ability and weaker emotional control tended to have slower walking speeds by middle age. 4.

The research team said genetic factors may explain the link between walking speed, brain capacity and physical health or that better brain health might promote physical activity, leading to better walking speed. Some of the differences in health and intellect may be the result of lifestyle choices individuals have made.

A. Those with a slower pace also scored less well in physical exercises such as hand-grip strength and biological markers of good health.

B. There are already signs in early life of who would become the slowest walkers.

C. In fact, based on a new series of experiments, they now believe the slower a person’s tendency to walk，the less able their brain.

D. Brain scanning during their final assessment at 45 showed the slower walkers tended to have lower total brain volume and less brain surface area.

E. Until now, however, no one knew it could signify underlying brain health so much earlier in life.

F. Researchers performed walking speed analysis on hundreds of middle-aged people, comparing their psychological results.