题目

You never played the video dance game? Now such games are used to help lose weight!        Like many other teenage boys, Jones loves sports. But at 5 feet, 175 pounds, he found his weight in trouble. His doctor wanted him to lose 50 pounds so that he may be a good football game player by the end of the summer.        Jones chose the popular Dance Revolution video game at home to increase his activity. He had lost about 10 pounds by changing his diet. Now, after two weeks’ playing the game, he has lost another 10!       A health study is being done by an insurance com下列图中有错误的是A.同名磁极间B.抽油烟机上指示灯C.滑动变阻器D.电磁铁的极性