In the meantime, at the edge of the square, Zhang Han sat quietly on a bench and looked at a dozen people going roller skating a short way ahead of them. The group of people all seemed to be about 18 or 19 years old. Several other people, who were in their twenties, led this group of people. They were very young, bursting with vitality and laughter. Unafraid to fall, they boldly tried different cool and handsome movements.

Next to them, many elderly people were using ...