Unit 1 1
Lesson 1 1
Lesson 2 7
Lesson 3 14
Lesson 4 21
Unit 2 28
Lesson 5 28
Lesson 6 34
Lesson 7 41
Lesson 8 48
Unit 3 55
Lesson 9 55
Lesson 10 61
Lesson 11 67
Lesson 12 74
Unit 4 81
Lesson 13 81
Lesson 14 87
Lesson 15 94
Lesson 16 100
Unit 5 107
Lesson 17 107
Lesson 18 113
Lesson 19 119
Lesson 20 125
Unit 6 132
Lesson 21 132
Lesson 22 138
Lesson 23 144
Lesson 24 150
Appendix Ⅰ 157
Version One 157
Version Two 169
Version Three 181
Chinese Version 192
Appendix Ⅱ 203
Reading Comprehension 203
Keys 218