Unit 1 1
Unit 2 14
Unit 3 27
Unit 4 43
Unit 5 58
Unit 6 71
Unit 7 86
Unit 8 100
Unit 9 113
Unit 10 128
Unit 11 144
Unit 12 159
Unit 13 173
Unit 14 188
Unit 15 202
Unit 16 217
Unit 17 231
Unit 18 245
Unit 19 262
Unit 20 278
Unit 21 293
附录:常用短语 308