HONG KONG — High school students in Hong Kong starting the new school year on Monday arrived to class wearing gas masks and joined hands to form human chains. University undergraduates held a strike, waved flags and chanted protest slogans.

After a summer of demonstrating in the streets, outside municipal offices and in the airport, students refuted the government’s wishful assertion that once they returned to school the months of pro-democracy protests that have roiled the city would come to an end.

“The government thinks it can quell the movement when students return to school, because we can only come out during the summer,” said Owen Lo, 16, a high school student. “But that’s not true.”

He said he was afraid of the repercussions he and other students might face but “seeing so many students selflessly gambling their future to express their demands to the government, it is infectious, and makes me want to come out and do something for Hong Kong.”