Unit 1 The Developing World 1
Topic 1 Our country has developed rapidly 1
Topic 2 What a large population! 22
Topic 3 The world has changed for the better 44
Unit 2 Loving Our Planet 68
Topic 1 Pollution causes too many problems 68
Topic 2 All these problems are very serious 90
Topic 3 Would you like to be a greener person? 110
Units 1-2综合测试 131
Unit 3 English Around the World 140
Topic 1 English is widely used throughout the world 140
Topic 2 English is spoken differently in different countries 160
Topic 3 Could you give us some advice on how to learn English well? 180
Unit 4 Amazing Science 202
Topic 1 Spaceships are mainly controlled by computers 202
Topic 2 When was it developed? 221
Topic 3 We will live in space one day 244
Units 3-4综合测试 265
参考答案 275