全學年成績平均分合格,且操行考勤紀錄是B+，還要留班，這是升留班政策。

I think that the school policy is very strict. 欠交功課和忘記帶用具次數多 are not a great fault. Did your parents ask your teachers to give you a chance to promote? If I were your class teacher, I must give you a chance. Try to ask the principal to explain the school policy. You promise them to hand in your homework on time and remember to bring the things. I think they may give you a chance.

如果這是學校政策就合理。
如果學校整體學生都是比你高,咁你要留班就對。
因為凡事都不能看表面,學校留班都是對你好,讀多一年可以是好事。