实用英语PDF电子书下载

Unit 1 A Clean World or a Polluted World 1

Unit 2 The Web Lifestyle 13

Unit 3 The International Space Station 23

Unit 4 The age of Cloning 33

Unit 5 Genetic Discovery Brings Worries as Well as Hope 47

Unit 6 Classification of Small Dams 60

Unit 7 Chinese Gardens 72

Unit 8 The Internet Pushes News Out，You and Computers Are Pulling It Down 86

Unit 9 Civil Engineering 98

Unit 10 What Are Computers? 117

Unit 11 Green Buildings 130

Unit 12 The Method of Scientific Investigation 142

Unit 13 A Theory About Genius 153

Unit 14 The Costs of Safety 167

Unit 15 Patents and Inventions 180

Key to Exercises 192

Unit 1 192

Unit 2 195

Unit 3 197

Unit 4 199

Unit 5 202

Unit 6 205

Unit 7 208

Unit 8 211

Unit 9 214

Unit 10 217

Unit 11 219

Unit 12 222

Unit 13 224

Unit 14 227

Unit 15 229