Contents 1
Unit 1 Changes in the Way We Live 1
Unit 2 Civil-Rights Heroes 17
Unit 3 Security 34
Unit 4 Extraterrestrials 50
Test One（Units 1-4） 66
Unit 5 How to Celebrate Holidays 79
Unit 6 The Human Touch 96
Unit 7 Making a Living 113
Unit 8 Cloning 130
Test Two（Units 5-8） 147
Key to Exercises 161
Tape Scripts 186