Unit 13 1
Unit 14 4
Unit 15 7
Unit 16 10
Unit 17 14
Unit 18 17
Unit 19 20
Unit 20 23
Unit 21 27
Unit 22 30
Unit 23 33
Unit 24 36
Unit 13 41
听力录音材料 41
Unit 14 44
Unit 15 47
Unit 16 50
Unit 17 54
Unit 18 57
Unit 19 61
Unit 20 64
Unit 21 68
Unit 22 71
Unit 23 75
Unit 24 78