Unit 1 Big Bucks the Easy Way 1
Unit 2 Deer and the Energy Cycle 16
Unit 3 Why Do We Believe That the Earth Is Round? 28
Unit 4 Flight 93:What I Never Know 41
Unit 5 To Lie or Not to Lie—The Doctor's Dilemma 54
Unit 6 How to Mark a Book 68
Unit 7 The Luncheon 81
Unit 8 The New Caves 95
Unit 9 The Education of a Physicist 108
Unit 10 Why People Work 121
Appendix 1 Key to Exercises（Unit 1-Unit 10） 135
Appendix 2 Chinese Translations of the Texts（Unit 1-Unit 10） 169
Appendix 3 Chinese Translations of the Reading Passages（Unit 1-Unit 10） 189