题目

My grandfather worked as a carpenter. On this particular day, he was building some crates（木箱）for the clothes his church was sending to an orphanage（孤儿院）in Brazil. On his way home, he found his glasses were gone. When he mentally replayed his earlier actions, he realized what happened. The glasses had slipped out of his pocket and fallen into one of the crates. His new glasses were heading for Brazil!  The Great Depression was at its height, and Grandpa had six children. He had spent twenty dollars for those glasses that very morning.  “It’s not fair,” he thought as he运动员跑到终点后，不能立即停下来。这是因为:A．运动员失去了惯性;　　　 　　　　 B．运动员具有惯性;C．运动员不受力的作用;　　　　　　 D．运动员的惯性大于阻力.