单选题 What is the main idea of this passage? [A] True friendship must help each other. [B] True friendship must be unconditional. [C] Friendship can be divided into two types.
【正确答案】 B
【答案解析】[考点] 主旨题 [解析] 从文中可以看出，文章的中心思想是“友谊必须是五条件的”。