Wang Shun of Zhejiang competes during the men's 200m freestyle heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Xu Jiayu of Zhejiang competes during the men's 100m backstroke heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Wang Jianjiahe of Liaoning competes during the women's 400m freestyle heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Yu Jingyao of Beijing competes during the women's 100m breaststroke heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Li Bingjie of Hebei competes during the women's 400m freestyle heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Fu Yuanhui of Zhejiang competes during the women's 100m backstroke heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Fu Yuanhui of Zhejiang competes during the women's 100m backstroke heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Fu Yuanhui of Zhejiang competes during the women's 100m backstroke heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]

Tang Qianting of Shanghai competes during the women's 100m breaststroke heat at the 2021 Chinese National Swimming Championships in Qingdao, East China's Shandong province, May 1, 2021. [Photo/Xinhua]