HONG KONG—A closely monitored national security trial involving 47 Hong Kong democracy campaigners charged with conspiracy to commit subversion, most of whom have been in custody since March, has been adjourned till March next year, a judge ruled on Monday. Magistrate Peter Law adjourned the next hearing till March 4, after making directions for the translation of nearly 10,000 pages of documentary evidence by year-end. Hong Kong laws bar media from publishing most details of pre-trial proceedings. The 47, who include opposition politicians, are among more than 150 people arrested under a national security law that Beijing imposed on the former British colony last year and that critics say erodes the freedoms promised when it was returned to Chinese rule in 1997. Chinese and Hong Kong officials deny the charge and say the law has returned order to Hong Kong, which was hit by months of sometimes violent pro-democracy, anti-China …