（下）Lesson 13 How to Grow Old

（下）Lesson 12 Selling the Post Ⅱ

（下）Lesson 11 Selling the Post Ⅰ

（下）Lesson 15 Edison Inventor of Invention

（下）Lesson 10 On Friendship

（下）Lesson 9 Forty Years On

（下）Lesson 8 How I Desined an A-Bomb in My Junior Year at Princeton

（下）Lesson 7 Some Meanings of Authentic Love

（下）Lesson 6 The Beauty of Britain

（下）Lesson 5 Frist Principles

（下）Lesson 4 Zero Hour: Forty-Three Seconds over Hiroshima

（下）Lesson 3 The Man Who Could Work Miracles Ⅱ

（下）Lesson 2 The Man Who Could Work Miracles Ⅰ

（下）Lesson 1 Courtesy： Key to a Happier World

（上）Lesson 16 A Social Event

（上）Lesson 15 Bribery---An Inevitable Evil?

（上）Lesson 14 Cipher in the Snow

（上）Lesson 13 Who Shall Dwell?

（上）Lesson 12 A Friend of the Environment

第九章计算机网络安全章节练习题