by Aaron Tam, Michelle Yun and Elaine Yu Agence France Presse HONG KONG, China (AFP) — President Xi Jinping arrived in Hong Kong on Thursday to mark 20 years since its return to China by Britain, with activists under arrest as authorities sought to avoid embarrassment during anniversary celebrations. A huge security operation shut down large parts of the normally throbbing city, with thousands of police deployed to keep away demonstrators against what they said […]