How much do you know about the solar system?The following passage will tell you.

The earth is a planet.It as well as seven _____ planets goes around the sun.We _____ the eight planets and the sun the solar system.The first planet,_____ the sun,is Mercury(水星).It is 58 million _____ from the sun.Venus(金星)is the second planet next to the sun,and _____ planet,the earth,is the third.It is 150 million kilometres from the sun.

Jupiter(木星),Saturn(土星),Neptune(海王星)and Uranus(天王星)are all _____ than the earth,_____ Venus,Mars and Mercury are smaller than the earth.

Animals,trees and humans can only _____ on the earth—the other planets in our solar system do not _____ air or water.Do any planets in other galaxies have ______?We don't know about it.

The world’s largest radio telescope was finished on Sept. 25, 2017 in China.

FAST is a five-hundred-meter telescope. It is also called Tian-yan ("The Eye of Heaven"), with a dish the sire of 30 football grounds, deep in the mountains of southwest China's Guizhou Province. The giant dish is built on a howl-like valley.

The surrounding area has "radio silence" as there are no towns and cities within a 5-kilometer radius（半径范围） and only one county center within 25 kilometers.

FAST is made up of 4,450 panels(面板). The second largest radio telescope is in Russia. The        bigger dish will be able to pick up weaker signals (信号).                         

The radio telescope is like an ear, listening to tell meaningful radio messages from white noise in     the universe. With the help of the telescope, we can receive weaker and more radio messages far away in space. It will help us to search for intelligent life outside of the Galaxy(银河系) and explore the origins（起源）of the universe. "Any of its discoveries will lead to a Nobel Prize," said Joseph Taylor, a Noble Prize winner.

The FAST project began in 2011. And the telescope is expected to remain the global leader for the next 10 to 20 years.