Dear (frend's name) ,
It was so nice to get your letter.
I am glad that you have pets! I think that it's very interesting to keep pets. They're funny and clever. Besides, you can play with them in fun games. Besides some people are fond of animals. They like to keep the animals at home. Although it's quite difficult.
As for me, I look after a dog. It's called Rex. This dog is very good. Last year my Reh attended a dog show and won. Of course, it's hard to have a pet. I have to feed it and take a walk.
Write back soon!
With love,
( Your name)