She's my best/oldest/closest friend - we've known each other since we were five.
He's a family friend/friend of the family.
This restaurant was recommended to me by a friend of mine.
We've been friends for years.
José and Pilar are (good) friends of ours.
We're (good) friends with José and Pilar.
She said that she and Peter were just (good) friends (= they were not having a sexual relationship).
I've made a lot of friends in this job.
He finds it difficult to make friends.