Dear Zi Lin,
I am very sorry to learn that you are unhappy now. But as a friend of yours, l don't think you should be unhappy.
I know that your family is not rich, so your parents can't afford to buy you clothes of famous brands, which makes you unhappy. Although we don't have much money, we can have a good mood every day. Many rich people have too much money, but they often feel bored and lonely. Your parents have sent you to school so that you can receive good education and have a bright future. This is not easy for your parents. So you should thank them. Don't ask for something that is out of your parents' reach. Don't be vain-glorious(虚荣的).
I also think you should put your heart into study. Read more books and you can get a lot from reading. Without the famous brand competition, you will become happy.
So you should decide not to feel so sorry and sad. You should smile and think you are luckier in life. I hope my advice will be helpful to you. Wish you happiness!
Yours,
ZhangMan
