Thank's for your letter.
Sorry, I haven't written for a long time, cuz i was busy.
My summer hollidays was great, I gone to the seaside with my family.Im playing with my friends all my summer hollidays.If you want, I can came to your birthday at next week, I think it will be very exciting and unforgetable.
Where would you want to go on your birthday?
Do you invite me ?
What do you want to get as your birthday gift?
Sorry, I need to help my mom.
Довольно не большое письмо, но все же основную часть изложил, можешь дополнить.