A trader selects bicycle tires on the first day of the 14th China North (Pingxiang) International Bicycles, Baby Strollers and Toys Fair in Pingxiang county, Hebei province, on April 17. The three-day event, held online and offline, has attracted over 1,500 traders from around the country. (Photo: Xinhua)

A trainer encourages his dog to leap through rings of fire in Guangxi Zhuang autonomous region on April 17. (Photo:people.com.cn)

Several baby egrets are seen at a bird nest in Huai'an city, East China's Jiangsu province, on April 18. (Photo: people.com.cn)

A child walks in the snow in Gade county, Guoluo Tibet autonomous prefecture in Qinghai province on April 19. (Photo: Xinhua)

People walk on stairs resembling a giant piano keyboard at a metro station exit leading to the Sichuan Conservatory of Music in Chengdu, Sichuan province on April 19. The stairs produce different notes and light effects when people step on them. (Photo: China news service))

Several adults and primary students hold globes to express their love of Planet Earth in Rugao city, East China's Jiangsu province, on April 20. The students were celebrating Earth Day, which falls on April 22. (Photo: IC)

A flock of Tibetan antelopes graze in Hoh Xil, Qinghai province on April 20. Every year, tens of thousands of pregnant Tibetan antelopes migrate to Hoh Xil in spring to give birth after mating in November or December, and leave with their offspring around August. (Photo: Xinhua)

A girl plays under the sunshine in Long'an county of Nanning, capital city of South China's Guangxi Zhuang autonomous region, on April 20. (Photo: IC)

An aerial photograph shows colors appearing on Salt Lake in Yuncheng, Shanxi province — the result of changes in the algae, on April 20. (Photo: IC)

Students read the Analects of Confucius at a primary school to experience traditional Chinese culture in Qingzhou, Shandong province on April 21. (Photo: China Daily)