A teacher checks plastic sheets which help prevent the spread of COVID-19 at a school in Bangkok, Thailand, June 23, 2020. Schools in Thailand are scheduled to reopen on July 1. (Xinhua/Rachen Sageamsak)

Teachers check plastic sheets and face shields which help prevent the spread of COVID-19 at a school in Bangkok, Thailand, June 23, 2020. Schools in Thailand are scheduled to reopen on July 1. (Xinhua/Rachen Sageamsak)

A teacher checks face shields which help prevent the spread of COVID-19 at a school in Bangkok, Thailand, June 23, 2020. Schools in Thailand are scheduled to reopen on July 1. (Xinhua/Rachen Sageamsak)

A teacher checks marks reminding students to keep social distancing at a school in Bangkok, Thailand, June 23, 2020. Schools in Thailand are scheduled to reopen on July 1. (Xinhua/Rachen Sageamsak)