My best friend has been like a sister to me.
我最要好的一个朋友待我亲如姐妹。
I had a long talk about this with my best friend
我和我最好的朋友就此事进行了长谈。
She's my best friend, and I really love her.
她是我最好的朋友，我真的很喜欢她。
She telephoned her best friend to vent her frustration
她给最要好的朋友打电话倾诉自己的沮丧。