3 . Working out can help teenagers boost their grades, a new study suggests. Adolescents who routinely engaged in moderate to vigorous（剧烈的）exercise showed long-term improvements in their academic performance, the British Journal of Sports Medicine study reported.
“Our study suggests that the effect of physical activity may be quite large,” John Reilly, a professor at the University of Strathclyde said. The researchers looked at a sample of about 5000 children who were involved in a long-term study that tracks children born in the UK between 1991 and 1992. When children reached 11 years old, their daily physical activity levels were measured using an accelerometer（加速器）for three to seven days. The device, similar to a pedometer（计步器）tracking the number of steps taken, recorded the average time children exercised, which was 29 minutes a day for boys and 18 for girls.
“The actual levels of daily physical activity at age 11 were quite low,” Mr. Reilly noted. The children had their academic performance tested at ages 11 and 13 with compulsory national tests for students, and also at 15 or 16 with the General Certificate of Secondary Education (GCSE) exam. The tests assessed the children’s abilities in English, math and science subjects. The results showed that the more children participated in moderate to vigorous physical activity, the higher their test scores were at age 11 in all three subjects. For girls, science scores were most strongly linked to exercise.
When children were tested again at age 13, their academic scores were still linked to how much they had exercised when they were 11 years old. By the time the youngsters took the GCSE exam, each 17-minute-per‑day increase in physical activity for the boys was linked to an improvement in their scores. Every additional 12-minute increase a day in exercise for the girls was also linked to an increased score, especially in the science category.
The researchers have called for more studies to look at the possible academic benefits that could be derived if students exercised the recommended 60 minutes or more a day.
1. What’s the study about?
| A．The influence of exercise on students’ scores. |
| B．The secrets of students’ ranking high in class. |
| C．The causes of students’ participating in sports. |
| D．The ways of improving students’ physical conditions. |
2. What is the function of the device used in the study?
| A．To record how long students exercise. |
| B．To record the walking speed of students. |
| C．To record how many steps students walk. |
| D．To record the number of calories students consume. |
3. What do the study’s results show?
| A．Students at age 11 do more exercise than at other ages. |
| B．Boys at age 13 get more benefits by doing more exercise. |
| C．Girls’ science scores are more closely related to exercise. |
| D．More and more students do exercise to improve their scores. |
4. What does the underlined word “derived” probably mean in the last paragraph?
| A．adopted. | B．acquired. |
| C．concluded. | D．displayed. |
