1 . Can exercise during childhood protect you against memory loss many decades later? Exercise early in life seems to have lifelong benefits for the brain, in rats at least.

“This is an animal study, but it shows that physical activity at a young age is very important—not just for physical development, but for the whole lifelong track of cognitive（认知的）development during ageing,”says Martin Wojtowicz of the University of Toronto, Canada.“ In humans, it may delay the appearance of Alzheimer's symptoms（阿茨海默氏症）, possibly to the point of preventing them.”

Wojtowicz’s team divided 80 young male rats into two equal groups, and placed running wheels in the cages of one group for a period of six weeks. Around four months later—when the rats had reached middle age—the team taught all the rats to connect an electric shock with being in a specific. When placed in the box, they froze with fear.

Two weeks later, the team tested the rats in three situations: exactly the same box in the same room, the same box with the room arranged differently, and a completely different box in a different room.

The rats without access to a running wheel when they were young now froze the same percentage of times in each of these situations, suggesting they couldn't remember which one was dangerous. But those that had been able to run in their youth froze 40 to 50 percent less in both changed box settings.

"The results suggest the amount of physical activity when we're young, at least for rats, has influence on brain and cognitive health—in the form of better memories—when we're older," says Arthur Kramer of Northeastern University in Boston, who has found that, in humans, exercise promotes the growth of new brain cells.

1. The study shows that_____.

A．physical activity is important for physical health

B．using the running wheels is of benefit to the rats’ growth

C．physical activity can prevent human’s Alzheimer's symptoms

D．the more exercise a rat has when young, the better memory it will possess when older

2. How are Paragraph 3 and 4 mainly developed?

A．By analyzing causes.

B．By giving an example.

C．By describing the process.

D．By showing differences.

3. What does the underlined word "it" in Paragraph 2 refer to?

A．Exercise.	B．Development.
C．Benefit.	D．Study.

4. What is the author's attitude towards the animal study?

A．Negative.	B．Objective.
C．Critical.	D．Doubtful.

2 . 根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
The right pair of exercise shoes can do a lot to prevent discomfort and injuries, personal trainers say．Here are some shopping tips:
­    1    Depending on your workout, shoes designed for walking, running, tennis, cross-training or another specialty will provide the best support for your feet．
Shop when you normally exercise．Feet actually get bigger throughout the day, sometimes swelling up as much as a half-size by nighttime．    2    
Try them on．Never grab a pair of exercise shoes based only on the size of footwear you normally buy．Bring the type of socks you’d wear to work out and go for a walk through the store．
    3    You should be able to spread your toes out comfortably．Make sure there’s about a half-inch of space between them and the front of the shoe．The back should fit snugly (warmly and comfortably) against your heel and not move up and down．If your feet are different sizes, buy based on the larger one．
Talk to an expert．Shoe salesmen and personal trainers can study your stride (步伐) and the shape of your feet．    4    
    5    Many trainers recommend switching footwear every three to five months, if possible, to maintain（保持）proper cushioning and support．
One tip: if you have to tie your shoes very tightly to feel a good amount of support, they may be ready to go．

A．Think about how much you can afford to buy the workout shoes．

B．Consider your type of exercise．

C．Focus on fit．

D．So don’t shop first thing in the morning if you often work out in the evening．

E．Pay more attention to new style shoes．

F．Replace worn shoes regularly．

G．Usually they can recommend the best shoes to guard against injuries．