This diptych photo taken on April 27, 2019 shows Xi Yungang, a welder with China Construction Third Engineering Bureau Co., Ltd., posing in his daily work outfit (L) and in a formal dress (R) in Xining, northwest China's Qinghai Province. In this series of portrait diptychs, frontline workers with China Construction Third Engineering Bureau Co., Ltd. appear in contrastingly different dress styles, but nevertheless manage to show the elegance of their professions. (Xinhua/Wu Gang)