Aerial photo shows the outdoor zone of the 2019 Changsha International Construction Equipment Exhibition in Changsha, central China's Hunan Province, May 15, 2019. The exhibition kicked off here on Wednesday. (Xinhua/Chen Zeguo)

People visit the 2019 Changsha International Construction Equipment Exhibition in Changsha, central China's Hunan Province, May 15, 2019. The exhibition kicked off here on Wednesday. (Xinhua/Chen Zeguo)