题目内容：

    Twenty minutes of exercise may help kids with ADHD(小儿多动症) settle in to read or solve a math problem, a new research suggests.

The small study, of 40 8～10 year-olds, looked only at the short-term effects of a single period time of exercise. But researchers warn that they are not saying exercise is the answer to ADHD.

But it seems that exercise may at least do no harm to kids' ability to focus, they say. And further studies should look into whether it's a good choice for managing some children's ADHD.

“This is only a first study,” said lead researcher Matthew B. Pontifex, of Michigan State University in East Lansing.

“We need to learn how long the effects last, and how exercise might combine with or compare to traditional ADHD treatments” like stimulant medications(刺激性药物), Pontifex explained.

He noted that there's been a lot of research into older adults. But little is known about kids, even though some parents, teachers and doctors have advocated exercise for helping children with ADHD.

So for their study, Pontifex and his colleagues found 20 children with diagnosed(诊断) or suspected ADHD, and 20 ADHD-free kids of the same age and family-income level.

All of the children took a standard test of their ability to ignore distractions(注意力分散) and stay focused on a simple task at hand - the main ability” that troubles kids with ADHD, Pontifex noted. The kids also took standard tests of reading, spelling and math skills.

Each child took the tests after either 20 minutes of treadmill(跑步机) exercise or 20 minutes of quiet reading (on separate days). Overall, the study found, both groups of children performed better after exercise than after reading.

On the test of focusing ability, the ADHD group was correct on about 80 percent of responses after reading, versus(相对于) about 84 percent after exercise. Kids without ADHD performed better -reaching about a 90 percent correct rate after exercise.

Similarly, both groups of kids scored higher on their reading and math tests after exercise, versus post-reading.

1.What does the new research suggest?

A.Exercising will make kids with ADHD stronger.

B.Exercising will help kids with ADHD focus better.

C.Exercising will help make math problems easier.

D.Exercising will help kids read more quickly.

2.What is the problem about the research into kids?

A.There is too much research into the older adults.

B.The research about the ADHD is enough.

C.The research about kids with ADHD is limited.

D.Exercise is not combined with traditional treatment.

3.Why did Pontifex’s team need 20 ADHD –free kids during the research?

A.They need to compare their performance with that of kids with ADHD.

B.They need them to do some reading and math problems after school.

C.They need them to take a standard test of their ability to ignore distractions.

D.They need them to take standard tests of reading, spelling and math skills.

4.What happened to the kids after exercising?

A.Kids with ADHD performed better than kids without ADHD in reading.

B.Kids without ADHD performed the same before and after exercising.

C.Both groups scored higher on their reading and math tests after reading.

D.Both kids with ADHD and without ADHD performed better after exercise.