Unit 13 The world's population 1
Unit 14 Shopping 12
Unit 15 A doctor for animals 21
Unit 16 The football match 32
Unit 17 The missing necklace 38
Unit 18 Mainly revision 44
情感篇 53
补充阅读材料 53
旅游篇 61
娱乐篇 66
校园篇 70
应用篇 77
动物篇 83
趣事篇 86
健康篇 93
Key to the exercises 100