CONTENTS 1
Lesson One 1
Text：Gravity 1
Grammar：Ⅰ．句子的种类 5
Ⅱ．状语从句（一） 6
Reading Material: Gravity and Spaceship 16
Lesson Two 18
Text：The Sun，the Moon and the Stars 18
Grammar：Ⅰ．形容词和副词的级 23
Ⅱ．状语从句（二） 26
Reading Material：Evaporation 33
Lesson Three 35
Text：Science and Facts 35
Grammar：主语从句，表语从句，宾语从句，同位语从句 41
Reading Material：Magnets 48
Lesson Four 50
Text：A Common Element 50
Grammar： What引导的从句 56
Reading Material：Air Pressure 60
Text： Light 62
Lesson Five 62
Grammar：定语从句（一） 67
Reading Material： Atoms 77
Lesson Six 79
Text：Cloud，Fog and Dew 79
Grammar：定语从句（二） 85
Reading Material： How Heat Travels 91
Lesson Seven 93
Text：A Story About Edison 93
Reading Material：Different Forms of Water 108
Grammar：复习 108
Lesson Eight 110
Text： Radar for Peaceful Purposes 110
Grammar：不定式（一） 116
Reading Material：Watson-Watt and Radar 123
Lesson Nine 126
Text： Li Shi-zhen 126
Grammar：不定式（二） 131
Reading Material： When and How to Collect Herbs 138
Text：Sound Has Speed 140
Lesson Ten 140
Grammar：动名词 147
Reading Material：Iron Smelting 153
Lesson Eleven 156
Text： Computers 156
Grammar：分词（一） 162
Reading Material：Chemical Reaction in a Living Body 170
Lesson Twelve 172
Text：Fire 172
Grammar：分词（二） 180
Reading Material： Electric Current 186
Lesson Thirteen 189
Text：Science and Scientific Research 189
Grammar：复习 202
Reading Material：Molecules 202
Lesson Fourteen 205
Text：Electron and Atom 205
Grammar：虚拟语气 210
Reading Material：How to Put Out a Fire 221
Text：Something About Electrification 223
Lesson Fifteen 223
Grammar：It用法小结 228
R eading Material：How to Build a Fire 237
Lesson Sixteen 238
Text：Expansion and Contraction 238
G rammar：As用法小结 245
Reading Material：Four Zones of the Earth 255
Lesson Seventeen 257
Text：Supersonic Planes 257
Reading Material：Fission and Fusion 272
Grammar：复习 272
Supplementary Readings 275
1．Water in the Air 275
2．What Are Magnets? 277
3．Can People Really Make Rain? 280
4．Force，Work，Energy and Power 282
5．How Changes Are Brought Abou+? 284
6．China's Own Path 290
Word Study索引 298
总词汇表 302