Narration(叙述) 1
Unit 1 1
Unit 2 11
Unit 3 21
Unit 4 30
Unit 5 41
Unit 6 50
Description(描述) 61
Unit 7 61
Unit 8 71
Unit 9 81
Unit 10 93
Unit 11 103
Exposition(说明) 113
Unit 12 113
Unit 13 123
Unit 14 134
Unit 15 143
Unit 16 154
Unit 17 163
Unit 18 174
Argumentation(议论) 184
Unit 19 184
Unit 20 194
Unit 21 205
Unit 22 214