From left, Jessie Cheung, Jerming Zhang, Clary Yeung and Maggie Ho with a protest banner at their school in Lai Chi Kok, Hong Kong, in July.CreditCreditLam Yik Fei for The New York Times
HONG KONG — They are sitting in orderly rows, wearing neatly pressed uniforms. But in this class, as they debate the merits of democracy and civil rights, Hong Kong high school students are prompting Beijing to worry that they are increasingly out of control.
