情景：班里来了一名新同学，学习跟不上。作为班长你要主动帮他补课，放学时，你请同学给父母带一张便条。
任务：请你用英语给父母写一封50左右的便条。告诉他们：
1 为什么今天回家会晚一些；
2 大约补多长时间的课；
3 什么时候到家。
请用下面格式：
Dear mum and dad ,
……
Bingbing
范文：
Dear mum and dad ,
I’m afraid I have to go home late today , because we have a new classmate . He is very poor in maths and English , so I need to help him to catch up with the class after school . We will stay at school for about an hour . I will get home at about six .
Bingbing