Dear Christine,
Thanks for your letter. It was great to hear from you. Sorry I haven't written for so long. I was really busy at school.
In your last letter you told me about an argument with your best friend Linda. I'm so sorry about it! I also simetimes argue with my best friend because of different mere trifles. After some time we apologize to each other. I think you also should apologize to Linda.
Great news about your visiting the local sport centre! How far is it from your house? Who do you attend it with? What do you like there?
Sorry, I have to go now to help my mom cooking dinner. Give my best regards to your parents. Write back soon.
Best wishes,
(Твоё имя, но помни, что оно должно быть без точки на конце! )