Are you preparing for a big test? If so, you may want to play some basketball in between hitting the books. Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels (血管), including those in the brain, stronger and more fully developed. Dr Cameron claims this allows people who exercise to concentrate better. She says, “ While we already know that exercise is good for the heart, exercise can really cause physical changes in the brain.”

The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement and physical activity show greater brain development than babies who are less physically active. With babies, even a little movement can show big results.

Older people can beef up (加强) their brain as well. Scientists from 11 universities studied a group of seniors ranging in age from 70 to 79. Their study showed a short-term memory increase of up to 40 per cent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for babies, exercise for seniors should involve some complexity (复杂). Learning some new skills or motions, such as with yoga or Tai Ji, helps open up memory paths in the brain that may not have used for a long time.

For most people, any type of physical activity that increases the heart rate is helpful. The main goal is to increase the brain’s flow of blood. And your brain can benefit from as little as three hours of exercise a week.

【小题1】The passage is mainly about _________.

A．how to exercise	B．how exercise helps the brain
C．how to get good scores in a test	D．how the brain can change

【小题2】According to the passage, what is the connection between exercise and brain development?

A．Exercise makes us happy.	B．The brain needs special mental exercise.
C．The more exercise, the bigger the brain.	D．Exercise helps the brain develop better.

【小题3】The least amount of exercise required to gain any benefit is __________.

A．Three hours per week	B．Forty hours per week
C．Three hours per day	D．Forty hours per month

【小题4】Why does the author think that yoga is fit for seniors?

A．It is easy to learn.	B．It can be done in groups.
C．It does not increase the heart rate.	D．It can learn some new skills.