1. (2021高三上·浙江期中) 阅读理解

Children's heavy digital media use is associated with a risk of being overweight later in adolescence. A recently completed study shows that six hours of leisure-time physical activity per week at the age of 11reduces the risk of being overweight at 14 years of age associated with heavy use of digital media.

Obesity in children and adolescents is one of the most significant health-related challenges globally. A study carried out by the Folkhalsan Research Center investigated whether a link exists between the digital media use of Finnish school-age children and the risk of being overweight later in adolescence. In addition, the study looked into whether children's physical activity has an effect on this potential link.

The study involved 4, 661 children who reported how much time they spent on sedentary (久坐的)digital media use and physical activity outside school hours. The study indicated that heavy use of digital media at 11 years of age was associated with a heightened risk of being overweight at 14 years of age in children who reported engaging in under six hours per week of physical activity in their leisure time. In children who reported being physically active for six or more hours per week, such a link was not observed.

The study also took into account other factors potentially impacting obesity, such as childhood eating habits and the amount of sleep, as well as the amount of digital media use and physical activity in adolescence. In spite of the confounding(混杂的) factors, the protective role of childhood physical activity in the connection between digital media use in childhood and being overweight later in life was successfully confirmed.

"The effect of physical activity on the association between digital media use and being overweight has not been extensively investigated in follow-up studies so far, "says Postdoctoral Researcher Elina Engberg. "In this study, the amount of physical activity and use of digital media was reported by the children themselves, and the level of their activity was not surveyed, so there is a need for further studies."

1. （1） The subjects of the study were

   A . surveyed three years later after the first one B . those who used sedentary digital media a lot C . 4661 school -aged children suffering from obesity D . lacking in sufficient leisure-time physical activity
3. （2） What does the underlined word "heightened" in paragraph 3 probably mean?

   A . major B . particular C . increasing D . slight
5. （3） What was the focus of the recent study?

   A . Different factors contributing to kids' overweight problem. B . The role of childhood eating habits in dealing with children's obesity. C . Impact of kids' exercise on the link between digital media use and obesity. D . Teens' health-related challenges resulting from heavy digital media use.
7. （4） What might be talked about in the following paragraph?

   A . Reasons for carrying out further studies. B . Guidelines for children and adolescents. C . Approaches to solving teens' weight problems. D . Connections between obesity and physical activity.