题目内容：

短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏词符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（﹨）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1.每处错误及其修改均仅限一词；

2.只允许修改10处，多者（从第11处起）不计分。

Dear Mandy，

I'm not doing well in my lessons at school，especial in maths. My dad says I must try hard be­cause he wants me go to university. He thinks I'm lazy，but it's not true. I work really hard，often study late into the night! I've tried to talk to my mother，but she always said I have to work as hard like my brother does. My brother doesn't study  very hard，and he always gets excellent grades. It's not fair!

The only thing I like it is art. My teacher says I'm the best student she's had for year. When I told my dad，all he said was，“ You mustn’t waste your time in art. You must focus your mind on your lessons! ”

I'm feeling quite puzzling as to what to do now. Would you please help me out?

Thanks a lot!

Yours sincerely， Lisa