Our planet Earth is one of nine planets which move round, or orbit, the sun.The Sun, planets, and their moons form the solar system.是什么意思_Our planet Earth is one of nine planets which move round, or orbit, the sun.The Sun, planets, and their moons form the solar system.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句