What are the pupils doing there? They're picking up the plastic bags on the street, but the plastic bags are so dirty.
They are doing that to remind people to protect the environment. You know, the white pollution is so serious these years.
Of course I know, but the pupils are young and there must be some viruses which are bad for them. Our hospital has many children falling sick because they pay a little attention to cleaning.
Sounds reasonable. The school may have told them what kinds of bags can't be picked up.