Unit 1 In th library Unit 2 Water sports Unit 3 Make our world more beautiful! Unit 4 Travel Unit 5 Have a good time! Unit 6 Mainly revision Unit 7 A man who never gave up Unit 8 Merry christmas! Unit 9 What is it made of? Unit 10 When was it built? Unit 11 Planting trees Unit 12 Mainly revision Unit 13 The worlds population Unit 14 Shopping Unit 15 A doctor for animals Unit 16 The football match Unit 17 The missing necklace Unit 18 Mainly rvision 附录一 课后习题参考答案 附录二 课文参考译文 · · · · · · (收起)