Lin Xu (L), wife of Chen Sitan, teaches a senior student during a group Tai Chi class at the club house at The Seasons in East Meadow, New York, the United States, Nov. 20, 2019. The ancient Chinese martial art Tai Chi has increasingly become a form of life for many New Yorkers, thanks to the efforts made by former world martial art champion Chen Sitan and his wife Lin Xu. (Xinhua/Wang Ying)