题目

Since soft drinks and fast-food restaurants became popular in Mexico, this country has become the second fattest nation in the world. Mexican health officals say it could replace the US as the most obese（肥胖的）country within 10 years if the situation doesn’t change. More than 71% of Mexican women and 66% of Mexican men are overweight, according to the latest national surveys. With diabetes（糖尿病）now Mexico’s leading cause of death, experts and leaders hope to make more efforts to encourage people to stop eating junk food or other fatty-food and to exercise more. But it will如图4所示的四个图的装置可以用来演示物理现象，则下列表述正确的是A．图甲可用来演示电磁感应现象B．图乙可用来演示磁场对电流的作用C．图丙可用来演示电流的磁效应D．图丁可用来演示电磁铁的磁性强弱与电流大小的关系