完形填空
We know the earth is a planet.There are seven other planets,and they go 1 the sun together.The eight planets and the sun are2 the solar system.The first planet,3 the sun,is Mercury(水星).It is 58 miIlion 4 from the sun.Venus(金星)is the second planetfrom the sun,and 5 planet,the earth,is the third.It is from the sun,and 55 planet,the earth,is the third.It is 2,650 million kilometres from the sun.
Jupiter(木星),Saturn(土星),Neptune(海王星)and Uranus(天王星)are all 6 than the earth,7 Venus,Mars and Mercury are smaller than the earth.
Animals,trees and humans can only 8 on the earth,because the other planets in our solar system don't 9 air or water.Do any 10planets in solar systems have life?We don't know about it.