There is a playgroud in front of our classroom on which we can have fun together.Teachers and classmates all trated me very well,which made me feel happy at school当然老师同学们对我好也可以用"They were very kind to me"我个人认为前半句用一般现在时是因为我对学校描述是一只存在的,而后半句用过去时是因为老师同学对我好是我的叙述,已成为过去,lz也可以用一般现在时,不过我觉得用过去时更好。