Dear friend,
Thanks a lot for your letter. Sorry for not writing you so long. I hope you are doing lovely.
In your letter you ask me about my family. Well, I want to say you that I really love my family. I have a mother, father, sister and brother. Moreover, we like to spend time together and go to the cinema. Besides, we like go to the park on Sunday.
Unfortunately, I must fly. My friend is waiting for me. Take care and keep in touch.
Lots of love,
(твое имя)