新概念二一共有96课， 每课都是一篇小短文。每课的内容大致有下面几个板块：文章，生词和短语，课文注释，译文，摘要写作，作文，语法，难点以及单项选择题。文章：每篇文章都以一个问题开头，你可以在阅读时带着问题，并试着回答它。
4-An exciting tripI have just received a letter from my brother, Tim. He is in Australia. He has been there for six months.
