题目

It's no surprise that sports can greatly benefit a child physically, psychologically, and socially. A 2008 Women's Sports Foundation Research Report concluded that children’s athletic participation is also associated with increased levels of family satisfaction, great achievement in study, and an overall better quality of life for children. And a study published in last month’s American Journal of Preventive Medicine showed that kids who are active at age 5 wind up with less body fat at ages 8 and 11. But one hotly debated discussion focuses on the kinds of sports kids should play如图，是滑动变阻器的结构示意图．变阻器连入电路时，有四种接法可起变阻作用，它们分别是接ADAD、接ACAC、接BDBD和接BCBC．通俗的说，变阻器只有接A或BA或B两个接线柱才起变阻作用．