阅读下列短文，从每题所给的A、B、C和D项中，选出最佳选项。
Our school is a green school．What makes it green？
First，we have a lot of trees．There are trees in front of and behind every building．Some trees are green only in spring and summer．And some are green all year round．The trees make our school look like a big forest.
And our school is a green one because we "go green". How do we go green？We have two green days every month．On green days，no students or teachers go to school by car．And we have clean﹣up Day every month．That day，students go to streets to pick up rubbish．Also，we have tree﹣planting Day every spring．We plant young trees on hills．We have three green clubs The members of the clubs look after those trees well．
Green is not only a colour．It is about life．Please go green with us and make the world a more beautiful place．
