In 1997,12-year-old American girl Caitlin and 14-year-old Zimbabwean (津巴布韦人) Martin became pen friends through their schools. They didn't realize at that time how their handwritten letters would change their lives.

    It all began as a school task. Everyone in Caitlin's class was supposed to choose a pen friend from another country. All the other kids picked countries like France or Germany, but Caitlin chose Zimbabwe because the name sounded exotic(异国的) and cool.

    Martin lived with his family in one of Zimbabwe's worst slums(贫民窟) where they shared one room with another family. And a bed was their only piece of furniture.

    When Caitlin's first letters reached Martin, they were simple and general. The two kids wrote about their favorite music and what they liked to do. But as Martin graduallyrevealedmore about his life and his letters started arriving written on pieces of trash, Caitlin realized what the living conditions were like for Martin. Without telling her parents, she began sending money with her letters—$ 20 at a time. While the money was not much to Caitlin, it meant more food for Martin's family and enabled him to pay his school fees.

    It lasted six years from their first exchange of letters to Martin's arrival in the United States. With the help of the money from Caitlin's parents later on, Martin finished his university and got his MBA from Duke University.

    Today, Caitlin and Martin aren't only best friends, but they also share their story in a book calledI Will Always Write Back. They want to encourage readers to look beyond their own lives and do something kind for others, which might greatly influence their lives.