A graduate attends the commencement at the Hockaday School in Dallas, Texas, the United States, on May 18, 2019. The class of 2019 students, wearing traditional white gowns and hats, celebrated Hockaday's commencement here on Saturday. (Photo: Xinhua)

Graduates attend the commencement at the Hockaday School in Dallas, Texas, the United States, on May 18, 2019. The class of 2019 students, wearing traditional white gowns and hats, celebrated Hockaday's commencement here on Saturday. (Photo: Xinhua)

Graduates pose for group photos during the commencement at the Hockaday School in Dallas, Texas, the United States, on May 18, 2019. The class of 2019 students, wearing traditional white gowns and hats, celebrated Hockaday's commencement here on Saturday. (Photo: Xinhua)

Graduates attend the commencement at the Hockaday School in Dallas, Texas, the United States, on May 18, 2019. The class of 2019 students, wearing traditional white gowns and hats, celebrated Hockaday's commencement here on Saturday. (Photo: Xinhua)

Graduates pose for group photos during the commencement at the Hockaday School in Dallas, Texas, the United States, on May 18, 2019. The class of 2019 students, wearing traditional white gowns and hats, celebrated Hockaday's commencement here on Saturday. (Photo: Xinhua)