Contents 1
Unit One Big Bucks the Easy Way 1
Unit Two Deer and the Energy Cycle 42
Unit Three Why Do We Believe That the Earth Is Round？ 72
Unit Four Jim Thorpe 100
Unit Five To Lie or Not to Lie—The Doctor's Dilemma 139
Unit Six How to Mark a Book 172
Unit Seven The Luncheon 202
Unit Eight The New Caves 238
Unit Nine Journey West 272
Unit Ten Why People Work 304
Appendix Ⅰ（四、六级题选答案） 341
Appendix Ⅱ（语法结构） 344
Appendix Ⅲ（语言要点） 347