A teacher supervises as students take their secondary school exam, at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

A teacher places books on students' desks before the start of a secondary school exam, at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

Students attend a secondary school exam, at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

Students attend a secondary school exam, at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

Students attend a secondary school exam, at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

A teacher gives instructions to students before the start of a secondary school exam, at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

Teacher passes sweets to students before the start of a secondary school exam at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

Students attend a secondary school exam at the auditorium of Paul Natorp Gymnasium, under restrictions imposed due to the coronavirus disease (COVID-19) outbreak, in Berlin, Germany April 26, 2021. REUTERS/Annegret Hilse

An assistant wearing a face mask distribute documents to students sitting for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students sit for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students have their documents checked before sitting for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students sit for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

An assistant wearing a face mask monitors students at the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students sit for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students sit for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students go through a temperature check before sitting for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students sit for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Students sit for the Diploma of Secondary Education (DSE) exams on April 26, 2021 in Hong Kong, China. Temperature checks and social distancing measures to avoid the spread of COVID-19 have have been put in place in the schools for over 50,000 candidates who will sit for the DSE examination this year. Anthony Kwan/Pool via REUTERS

Medical exam rooms is to be set up inside exhibit hall A of the Convention Center where migrant children found at the border without a parent will be temporarily housed, in Long Beach, U.S., April 22, 2021. The center is able to house up to 1,000 children. Picture taken April 22, 2021. Brittany Murray/Pool via REUTERS

An English dictionary is placed on a table during graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

A teacher oversees students during graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

A teacher oversees students during graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

Students attend graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

Students attend graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

A teacher oversees students during graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

Students attend graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

Students attend graduation exams in English at the sports hall of Gesamtschule Windeck (comprehensive school Windeck) during the spread of COVID-19 pandemic in Windeck-Herchen, Germany April 23, 2021. REUTERS/Wolfgang Rattay

A worker wearing a protective face mask disinfects Iraqi students as they arrive to take their mid-year exams, amid the spread of the coronavirus disease (COVID-19) at a school in Baghdad, Iraq March 22, 2021. REUTERS/Khalid al-Mousily

Iraqi students wearing protective face masks take their mid-year exams, amid the spread of the coronavirus disease (COVID-19) at a school in Baghdad, Iraq March 22, 2021. REUTERS/Khalid al-Mousily

Iraqi students wearing protective face masks take their mid-year exams, amid the spread of the coronavirus disease (COVID-19) at a school in Baghdad, Iraq March 22, 2021. REUTERS/Khalid al-Mousily

Iraqi students wearing protective face masks take their mid-year exams, amid the spread of the coronavirus disease (COVID-19) at a school in Baghdad, Iraq March 22, 2021. REUTERS/Khalid al-Mousily

Iraqi students wearing protective face masks take their mid-year exams, amid the spread of the coronavirus disease (COVID-19) at a school in Baghdad, Iraq March 22, 2021. REUTERS/Khalid al-Mousily

Students arrive for the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19), at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

A man reads a book as people gather before the beginning of the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19), at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

A student reads a book as people gather before the beginning of the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19), at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

Students gather before the beginning of the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19), at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

Students arrive for the ENEM, Exame Nacional do Ensino Medio (National High School Exam), at UNIP Vergueiro test site, during the outbreak of the coronavirus disease (COVID-19), in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

Students and their families gather before the beginning of the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19), at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

Rogerio Souza hugs his daughter Isabelle before she enters for the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19) at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

People gather before the beginning of the ENEM, Exame Nacional do Ensino Medio (National High School Exam), during the outbreak of the coronavirus disease (COVID-19) at UNIP Vergueiro test site in Sao Paulo, Brazil January 17, 2021. REUTERS/Amanda Perobelli

A student prays ahead of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

A student waits for the start of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

A student checks the time as the others wait for the start of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

Students wait for the start of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

A student adjust her mask ahead of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

Students wait for the start of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

Students wait for the start of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic at an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji/Pool

A father prays for his child's success in the annual college entrance examinations, in front of an exam hall in Seoul, amid the coronavirus disease (COVID-19) pandemic in South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

Students and their family members walk in front of an exam hall ahead of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic, in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

Students and their family members walk in front of an exam hall ahead of the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic, in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

Family members wait in front of an exam hall as their children take the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic, in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

Family members wait in front of an exam hall as their children take the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic, in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

A student hugs family members before she takes the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic in front of an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

A mother hugs her daughter before she takes the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic in front of an exam hall in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

South Korean high school students and exam retakers arrive at an exam hall to take the annual college entrance examinations amid the coronavirus disease (COVID-19) pandemic in Seoul, South Korea, December 3, 2020. REUTERS/Kim Hong-Ji

A mother prays for children’s success in the college entrance examinations amid the coronavirus disease (COVID-19) pandemic, at a Buddhist temple in Seoul, South Korea, December 2, 2020. REUTERS/Kim Hong-Ji

Buddhist believers pray for their children’s success in the college entrance examinations amid the coronavirus disease (COVID-19) pandemic, at a Buddhist temple in Seoul, South Korea, December 2, 2020. REUTERS/Kim Hong-Ji

Buddhist believers pray for their children’s success in the college entrance examinations amid the coronavirus disease (COVID-19) pandemic, at a Buddhist temple in Seoul, South Korea, December 2, 2020. REUTERS/Kim Hong-Ji

A mother prays for children’s success in the college entrance examinations amid the coronavirus disease (COVID-19) pandemic, at a Buddhist temple in Seoul, South Korea, December 2, 2020. REUTERS/Kim Hong-Ji TPX IMAGES OF THE DAY

A mother lights a candle as she prays for children’s success in the college entrance examinations amid the coronavirus disease (COVID-19) pandemic, at a Buddhist temple in Seoul, South Korea, December 2, 2020. REUTERS/Kim Hong-Ji