资源介绍：
适合一年级的有关太阳系的英文读物高清PDF源文件
Chapter 1 The Mysterious Movement of the Moon . 2
Chapter 2 What Causes Night and Day? . 6
Chapter 3 Longer and Shorter Times of Daylight . 12
Chapter 4 Why Does the Moon Seem to Move? . 16
Chapter 5 How Does the Starry Sky Change?. 20
Chapter 6 Science in Action . 24
