Unit 1 Topic 1 Our country has developed rapidly.

• Unit 1 Topic 1 Our country has developed rapidly.

Unit 1 Topic 2 The population in developing countries is growing faster.

• Unit 1 Topic 2 The population in developing countries is growing faster.

Unit 1 Topic 3 The world has changed for the better.

• Unit 1 Topic 3 The world has changed for the better.

Review of Unit 1

• Review of Unit 1

Unit 2 Topic 1 Pollution has caused too many problems.

• Unit 2 Topic 1 Pollution has caused too many problems.

Unit 2 Topic 2 All these problems are very serious.

• Unit 2 Topic 2 All these problems are very serious.

Unit 2 Topic 3 What can we do at home to protect the environment?

• Unit 2 Topic 3 What can we do at home to protect the environment?

Review of Units 1-2

• Review of Units 1-2

Unit 3 Topic 1 English is widely speaken throughout the world.

• Unit 3 Topic 1 English is widely speaken throughout the world.

Unit 3 Topic 2 Some things usually have different meanings in different cultures.

• Unit 3 Topic 2 Some things usually have different meanings in different cultures.

Unit 3 Topic 3 Could you give us some advice on how to learn English well.

• Unit 3 Topic 3 Could you give us some advice on how to learn English well.

Review of Unit 3

• Review of Unit 3

Unit 4 Topic 1 When was it invented?

• Unit 4 Topic 1 When was it invented?

Unit 4 Topic 2 I'm excited about the things that will be discovered in the future.

• Unit 4 Topic 2 I'm excited about the things that will be discovered in the future.

Unit 4 Topic 3 China is the third nation that sent a person into space.

• Unit 4 Topic 3 China is the third nation that sent a person into space.

Review of Units 3-4

• Review of Units 3-4