How often do you exercise？A new study finds that most kids aged 12 to 15 aren't getting enough physical activity.The results are based on about 800 kids.As part of the study,the young teens tracked and reported on their own activity levels,and took physical exams.
The US fitness guidelines recommend an hour or more of physical activity every day.According to the study,only 1 in 4 kids in the US get enough physical activity.
"It's certainly very worrying to see that our kids are engaging in such a limited amount of physical activity each day," said Dr.Stephen Pont.He is an expert on children's health.
Few kids in the survey met the guidelines for physical activity that raises the heart rate and makes them breathe harder.Overall,about 25% said they got an hour of that kind of violent exercise every day.Kids also reported on which activities they did most often outside of the school gym class--basketball for boys and running for girls.
The study found that obese（肥胖的）teens were less active than normal-weight girls and boys.Overweight girls were slightly less active than normal-weight girls,but levels were similar among overweight and normal-weight boys.The study also said that the overall obesity rate for children aged 2 to 19 is 17%，or about 12.5 million kids.
"There's always room for improvement," said health expert Tala Fakhouri,who was the lead author of the study.She also said the results provide useful information to help with fitness campaigns such as Lets Move,which was launched by Michelle Obama in 2010.To inspire kids to eat right and get in shape,Michelle visited schools and held exercise events.She also called on schools to offer regular gym classes.
The study also suggests kids who get physical education at school may get better grades.



What is the result of the new study？ ______

A. It is important to take physical exams.
B. Most US kids don't get enough exercise.
C. Kids should get physical activity every day.
D. 800 kids don't get enough physical activity.

What's the purpose of the campaign Let's Move？ ______

A. To help kids to keep fit.
B. To hold exercise events.
C. To offer regular gym classes.
D. To provide useful information.

According to the study,the children with enough exercise ______

A. do better in their studies
B. try their best to get in shape
C. be more willing to help others
D. be less active than fat children

What does the underlined word "launched" in the sixth paragraph probably mean？ ______

A. visited
B. stopped
C. started
D. improved