Unit 13 The USA

Unit 14 Roots

Unit 15 Study skills

Unit 16 Social and personal

Unit 17 My teacher

Unit 18 Office equipment

Unit 19 New Zealand

Unit 20 Gandhi

Unit 21 Who gets the money？

Unit 22 Bees

Unit 23 The find of the century

Unit 24 Finding jobs

补充练习参考答案