Unit4 Astronomy the science of the stars 教学资源Part 2: Teaching Resources(第二部分：教学资源)Section 1: A text structure analysis of HOW LIFE BEGAN ON THE EARTH1. Type of writing and summary of the textType of writingThis is a descriptive writing.Main idea of the passageThe earth came into being after the “Big Bang”. Then small plants came growing in the water, followed by green plants appearing on land. In the end appeared small clever animals.Topic sentence of 1st paragraphAfter the “Big Bang”, the earth was just a cloud of energetic dust.Topic sentence of 2nd paragraphThe earth was different because of the arrival of small plants growing in the water.Topic sentence of 3rd paragraphMany millions of years later the first green plants began to appear on land.Topic sentence of 4th paragraphSmall clever animals appeared and spread all over the earth.2. A tree diagramSection 2: Background information for Unit 4 Astronomy: the science of the stars1. THE PLANETS 行星Although we live in a very small piece of the Universe, it's still where we call home and it's a very interesting place. The nine planets that make up our solar system range from very tiny rocky planets to huge gas giants featuring fascinating ring systems. Mercury 水星Mercury is the closest planet to the Sun. Its surface has many thousands of impact craters as a result of being bombarded by objects since the solar system's early days. Since Mercury has no protective atmosphere, the temperature on the surface ranges from extremely hot on the side facing the Sun to extremely cold on the side that faces away from the Sun. Venus 金星（太白星）用心 爱心 专心 117 号编辑 1 After the “Big Bang”, the earth being just a cloud of ene...
