Linda Evans was my best friend－like the sister I never had. We did everything together: piano lessons, movies, swimming, horseback riding.

　　When I was 13, my family moved away. Linda and I kept in touch through letters, and we saw each other on special time－like my wedding and Linda's. Soon we were busy with children and moving to new homes, and we wrote less often. One day a card that I sent came back, stamped "Address Unknown." I had no idea how to find Linda.

　　Over the years, I missed Linda very much. I wanted to share happiness of my children and then grandchildren. And I needed to share my sadness when my brother and then mother died. There was an empty place in my heart that only a friend like Linda could fill.

　　One day I was reading a newspaper when I noticed a photo of a young woman who looked very much like Linda and whose last name was Wagman－Linda's married name. "There must be thousands of Wagmans," I thought, but I still wrote to her.

　　She called as soon as she got my letter. "Mrs. Tobin!" she said excitedly, "Linda Evans Wagman is my mother."

　　Minutes later I heard a voice that I knew very much, even after 40 years, laughed and cried and caught up on each other's lives. Now the empty place in my heart is filled. And there's one thing that Linda and I know for sure: we won't lose each other again!

They didn't often write to each other because they____?（　　）

• A.got married
• B.had little time to do so
• C.didn't like writing letters
• D.could see each other on special time