Dorothy and Sarah continued to write to each other, and so began a life-long friendship.多萝西和萨拉继续保持通信，就这样开始了一段持续终生的友谊。The mission of International House is to enable students of different cultures to live together and build life-long friendships.国际之家的宗旨就是让不同文化背景的学生住在一起，建立终身的友谊。