Graduates pose for photos during the 2018 commencement ceremony of Xi'an Jiaotong University in Xi'an, northwest China's Shaanxi Province, June 23, 2018. Photo:Xinhua

Graduates take selfie during the 2018 commencement ceremony of Xi'an Jiaotong University in Xi'an, northwest China's Shaanxi Province, June 23, 2018.Photo:Xinhua

Graduates attend the 2018 commencement ceremony of Xi'an Jiaotong University in Xi'an, northwest China's Shaanxi Province, June 23, 2018.Photo:Xinhua

A graduate receives diploma during the 2018 commencement ceremony of Xi'an Jiaotong University in Xi'an, northwest China's Shaanxi Province, June 23, 2018.Photo:Xinhua