BEIJING (AP) — It only took moments after Zhang Peimeng crossed the finish line for the Chinese 4x100-meter relay team's historic medal to be upgraded from bronze to silver. Usain Bolt anchored the Jamaican team to a big win, and was followed across the line by the United States and China, giving the host nation its first medal in the 4x100 at a major international meet. After the race, Xie was asked about the pair of two-month training camps that the Chinese relay squad spent in the United States. "The most important thing I learned in the U.S.