![](http://www.ecns.cn/hd/2020/04/20/a55c1e83bc95491582e182e3e9d0d562.jpg)
A teacher welcomes students before the start of their high school graduation exams, during the spread of the coronavirus disease (COVID-19), at the Gymnasium Steglitz school in Berlin, Germany, April 20, 2020. (Photo/Agencies)
![](http://www.ecns.cn/hd/2020/04/20/b96e1c70422141a09f93a960009807f4.jpg)
A teacher welcomes students before the start of their high school graduation exams, during the spread of the coronavirus disease (COVID-19), at the Gymnasium Steglitz school in Berlin, Germany, April 20, 2020. (Photo/Agencies)
![](http://www.ecns.cn/hd/2020/04/20/21f068416bd64a25a05cc7f14e8934cf.jpg)
A teacher welcomes students before the start of their high school graduation exams, during the spread of the coronavirus disease (COVID-19), at the Gymnasium Steglitz school in Berlin, Germany, April 20, 2020. (Photo/Agencies)
![](http://www.ecns.cn/hd/2020/04/20/96e65139f40f4aaea241d6eead6c178d.jpg)
Disinfectant is seen before the start of the high school graduation exams, during the spread of the coronavirus disease (COVID-19), at the Gymnasium Steglitz school in Berlin, Germany, April 20, 2020. (Photo/Agencies)
![](http://www.ecns.cn/hd/2020/04/20/30f50c34c5e04e71998b8c292398a686.jpg)
A teacher welcomes students before the start of their high school graduation exams, during the spread of the coronavirus disease (COVID-19), at the Gymnasium Steglitz school in Berlin, Germany, April 20, 2020. (Photo/Agencies)