eight principal planets

• n. 八大行星

例句

用作名词 (n.)

1. The earth is one of the eight Planets.
   地球是八大行星之一。
2. Leading astronomers declared Thursday that Pluto is no longer a planet under historic new guidelines that downsize the solar system from nine planets to eight.
   要天文学家周四宣布，在发布历史性的新方针后，太阳系九大行星缩减为八大行星，冥王星已不再是行星。