A
It's very big and hot.
It's the sun.
It's blue and green. We live (住在) here.
It's Earth.
It has a big ring (光环).
It's Saturn.
It's small and red.
It's Mars.
It's the biggest (最大) planet.
It's Jupiter.
There are so many in space. They are big and bright (明亮).
They are stars.
It's very small and white.
It's the moon.
They aren't people. They live (住在) in space (太空).
They are aliens (外星人).
It's blue and very cold.
It's Neptune.
It's very big. It can help you fly to space (太空).
It's a rocket.
It's the first planet.
It's Mercury.
It's the second planet.
It's Venus.
They are people. They fly to space (太空).
They are astronauts (宇航员).
There are eight of these in our solar system (太阳系).
There are eight planets.
How many planets are there in our solar system (太阳系)?
There are eight planets in our solar system.