A、Long distance race. B、100-metre race. C、Fun games. D、Watching TV. C原文说这一小时的锻炼时间不需要进行计时跑步，只需要通过感兴趣的游戏逐渐积累起来。

The American Academy of Pediatrics recently advised parents to make sure children get an hour of physical activity each day to fight obesity. But you don’t have to force your kids to de timed races. That hour can be ac- cumulated through games that you both enjoy.
    "For any individual child the key is to get them to do activities that are fun so they’ll be interested and want to do more of that activity," said Dr. Eric Small, a co-author of the policy statement.
    For example, walk your child to school or the bus stop by playing the classic game Follow the Leader. The leader can jump up on a curb, hop on one foot five times, or limbo under a tree branch. The game can get kids as young as 2 moving and help them learn to embrace an active lifestyle.
    Getting kids moving can even be as simple as getting them walking or bicycling. Set aside a time for the activity and set a goal of reaching a landmark or just cruising around the neighborhood for an hour. Take your child ice-skating or swimming or just running through the sprinkler, advises Marsha Smith, a physical education teacher. Take an older child golfing and walk the course instead of renting a cart. "At first, it’s an honor," Smith said. "Spending time with a parent or other caregiver motivates them."
    Having trouble getting things started? Kennedy suggests getting started by replacing something kids hate with physical, activity. So do the dishes for the kids white they head outside for a bike ride, or let them stay up an hoar later for a game of flashlight tag.