单元主题1.Friendship 2.English around the world 3.Travel journal 4.Earthquakes 5.Nelson Mandela-a modern hero 6.Cultural relics 7.The Olympic Games 8.Computers 9.Wildlife protection 10.Music 11.Festivals around the world 12.Healthy eating 13.The Million Pound Bank Note 14.Astronomy:the science of the stars15.Canada-\"The True North\"16.Women of achievement 17.Working the land 18.A taste of English humour 19.Body language 20.Theme parks 21.Great scientists 22.The United Kingdom 23.Life in the future