The Earth is a planet. It and seven other planets go {#blank#}1{#/blank#} the Sun. We {#blank#}2{#/blank#} (call)the eight planets and the Sun the solar system. {#blank#}3{#/blank#} first planet, next to the Sun, is Mercury(水星). It is 58 million {#blank#}4{#/blank#} (kilometer)from the Sun. Venus(金星)is the second planet from the Sun, and {#blank#}5{#/blank#} (we)planet, the Earth, is the third. It is 150 million kilometers from the Sun.

    Jupiter(木星), Saturn(土星), Neptune(海王星)and Uranus(天王星)are all {#blank#}6{#/blank#} (big)than the Earth,  {#blank#}7{#/blank#} Venus, Mars and Mercury are smaller than the Earth.

    Animals, trees and humans can only live {#blank#}8{#/blank#} the Earth-the other planets in our solar system do not have air {#blank#}9{#/blank#} water. Do any planets in other solar systems have {#blank#}10{#/blank#} (life)? We don't know about it.