extragalactic systems的用法和樣例：
例句
- Earth was a beautiful place, located on the fringes of one of the galactic systems and easily reached from other galaxies.
地球是一個美麗的地方，位於銀河系的一條旋臂上，從其它星系容易到達。 - The original plan was for Earth to be an exchange center of information for all the different galactic systems.
最初的計劃就為了使地球成為一個所有不同銀河系的系統的信息交流中心。
