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Cai Zelin of China competes during the men's 20km race walk at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 5, 2019. (Xinhua/Jia Yuchen)

Cai Zelin of China competes during the men's 20km race walk at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 5, 2019. (Xinhua/Jia Yuchen)