Unit1 The Changing World Topic1 Our country has developed rapidly.
Unit1 The Changing World Topic2 The population in developing countries is growing faster.
Unit1 The Changing World Topic3 The world has changed for the better.
Unit2 Saving the Earth Topic1 Pollution has caused too many problems.
Unit2 Saving the Earth Topic2 All these problems are very serious.
Unit2 Saving the Earth Topic3 What can we do at home to protect the environment?
Unit3 English Around the World Topic1 English is widely speaken throughout the world.
Unit3 English Around the World Topic2 Some things usually have different meanings in different cultures.
Unit3 English Around the World Topic3 Could you give us some advice on how to learn English well.
Unit4 Amazing Science Topic1 When was it invented?
Unit4 Amazing Science Topic2 I’m excited about the things that will be discovered in the future.
Unit4 Amazing Science Topic3 China is the third nation that sent a person into space.