题目

Something is happening to kids in the US today. They are getting more and more out of shape. Many of them sit inside watching TV or using the computer instead of playing sports. But there are some kids who still enjoy different sports and here are three of them.Ted is learning how to swim. He takes swimming lessons at the community pool every Monday and Wednesday afternoon. Before he started taking swimming lessons, Ted did not know how to swim at all. In fact, he was a little afraid of the water. Now, Ted enjoys swimming. So far, he has learned three styles of swimming.Tom favors running. He 足球运动员将足球踢向空中，下列描述足球在空中向斜上方飞行过程中某时刻的受力图中，正确的是（G为重力，F为脚对球的作用力，Ff为空气阻力）　 [     ]A．B．C．D．