 Complete the following phrase:  In age-specific categories he won several medals. At the 2008 Asian Junior Championships he won a silver medal in the 4 × 100 metres relay and a gold medal in the 4 × 400 metres relay. At the 2010 Asian Junior Championships he won gold medals in the 200 metres, 4 × 100 and 4 × 400. At the 2008 World Junior Championships he competed in the 200 metres without progressing from the heat and finished eighth at the 2008 World Junior Championships. At the 