1 A Our Solar System 1
1 B Is There Life on Mars? 3
2 A A Journey Through the Eye 5
2 B Eye Care Through the Ages 7
3 A Herbs:Plants of Many Uses 9
3 B The Art of Herb Gardening 11
4 A Early Discoveries in Electricity 13
4 B What Causes Static Electricity? 15
5 A What Makes a Hurricane? 17
5 B The Day of the Hurricane 19
6 A Where Have All the Grasslands Gone? 21
6 B Hunting Buffalo:A Way of Life 23
7 A Arachnids 25
7 B Spiders That Lasso Their Prey 27
8 A Training to Be an Astronaut 29
8 B Disappointments and Triumphs of Female Astronauts 31
9 A What Good Is Sleep? 33
9 B Helpful Hints for Falling Asleep 35
10 A HoW Sedimentary Rock Forms 37
10 B Fossils:A Record of Life on Earth 39
11 A Surviving the Tides 41
11 B Getting the Salt out of Salt Water 43
12 A The Invention of the Camera 45
12 B Preparing for the Science Fair 47
13 A Simple and Compound Machines 49
13 B Bicycles on the Move 51
14 A The Spectrum of Light 53
14 B Recipe for a Rainbow 55
15 A Recycling Can Reduce Pollution 57
15 B Fighting Air Pollution 59
16 A Exploring the Undersea World 61
16 B Snorkeling 63
17 A The Endangered Everglades 65
17 B Protecting Wild Animals 67
18 A A Meal of Wild Forest Plants 69
18 B The Origin of Corn 71
19 A What Is Sound? 73
19 B Pleasant and Unpleasant Sounds 75
20 A Climate and the Change of Seasons 77
20 B Repairing the Ozone Layer 79
21 A Earthquakes 81
21 B Not Aftershocks After All 83
22 A Dinosaurs:All Shapes and Sizes 85
22 B Are Birds Related to Dinosaurs? 87
23 A Energy and Motion 89
23 B The Science of Kickball 91
24 A Sayings About Animals 93
24 B An Unusual Bird and Its Unforgettable Food 95
25 A Life Cycles of Wildflowers 97
25 B Searching for Desert Wildflowers 99
附录 101
Answer Key 101
Reading Rate 103
Comprehension Score 104
Comprehension Skills Profile 105