一、根据句意，从方框中选择适当的词并用其正确形式填空。
heat, object, degree, surface, universe
1. As we know, water freezes (结冰) at zero ______ Celsius (摄氏度).
2. All plants need water and the ______ of the sun to grow.
3. Oceans cover the largest area on the ______ of the earth.
4. Now, we can see many bright stars and other ______ in the night sky.
5. When we talk about the ______, we mean the sun, the moon, the earth and other planets in it.

二、根据中文意思完成句子。
1. 月亮是地球的卫星，它围绕着地球旋转。
The moon is a satellite of the earth, and it ______ ______ the earth.
2. 你知道科学家是怎么把宇宙飞船发送到太空的吗？
Do you know how scientists ______ the spaceship ______ space?
3. 地球要比太阳小得多。
The earth is ______ ______ ______ the sun.
4. 我认为火箭是探索太空最重要的工具。
I think rockets are ______ ______ ______ tools for exploring the space.
5. 没有人知道别的星球上有没有生命。
______ ______ ______ if there are living things on other planets.
6. 我们要爱护地球，因为它是我们唯一的家园。
We must love and take care of the earth because it is ______ ______ ______ ______ us.

三、按要求完成句子。
1. The earth is a natural satellite of the sun.（改为一般疑问句，并作出肯定回答）
—______ ______ ______ a natural satellite of the sun?
—Yes, ______ ______.
2. The sun provides light and warmth for the earth.（对画线部分提问）
______ does the sun ______ ______ the earth?
3. There are eight planets in the solar system.（对画线部分提问）
______ ______ planets are there in the solar system?
4. It's about 384,400 kilometers away from the earth to the moon.（改为同义句）
The moon ______ ______ about 384, 400 kilometers ______ ______ the earth.
5. I'm 65 kilos heavy. My brother is 60 kilos heavy.（用比较级改写句子）
I ______ ______ ______ my brother.
6. It is the largest and brightest object in the solar system.（对画线部分提问）
______ ______ you ______ ______ the sun?