The Earth is a beautiful place. There are forests and rivers, mountains and fields. We live _____ the Earth. It's our home. But how much do you know about it? Let me tell you _____ about our Earth.

The Earth is like _____ big ball. Like the other seven planets(行星),the Earth is running around the Sun. It's the third nearest planet to the Sun. It takes the Earth about 365 days _____ around the Sun. At the same time, the Earth is going around itself. If you are in space, you can see lots of white clouds over the surface(表面) of the Earth. Through the clouds, you can see the blue colour of the seas _____ the brown colour of the land. About 70% of the Earth is covered______ water.

The Earth used to be very______ and beautiful. But today there______ too much pollution. People cut down trees and kill animals. _____ put rubbish into rivers and seas. So, more and more water is becoming dirty. We must stop ______ these thing.