Photo taken with a mobile phone shows people visiting the China Pavilion of the Beijing International Horticultural Exhibition in Beijing, capital of China, on May 25, 2019. (Xinhua/Wei Mengjia)

Photo taken with a mobile phone shows people visiting the China Pavilion of the Beijing International Horticultural Exhibition in Beijing, capital of China, on May 25, 2019. (Xinhua/Wei Mengjia)

Photo taken with a mobile phone shows people visiting the China Pavilion of the Beijing International Horticultural Exhibition in Beijing, capital of China, on May 25, 2019. (Xinhua/Wei Mengjia)

Photo taken with a mobile phone shows people visiting the China Pavilion of the Beijing International Horticultural Exhibition in Beijing, capital of China, on May 25, 2019. (Xinhua/Wei Mengjia)

Photo taken with a mobile phone shows people visiting the China Pavilion of the Beijing International Horticultural Exhibition in Beijing, capital of China, on May 25, 2019. (Xinhua/Wei Mengjia)