The Berlin Athletics World Championship is about to begin, and defending champion Liu Xiang will not be able to participate due to injury. However, he has not given up his efforts to return to the competition. Last week, Dr. Clanton, an American expert, conducted a comprehensive examination for Liu Xiang, and the optimistic results finally allowed Xiang to start wearing spike shoes to practice hurdling. This also means that Liu Xiang's comeback is beginning...