planetary system的用法和樣例：
例句
- Travel to the planetary systems of other stars is a much more formidable undertaking.
要航行到其他恒星的行星系中去是件極難實(shí)現的事。 - Astronomers today announced the discovery of another planet orbiting a distant star, making it the most crowded planetary system outside our own.
天文學(xué)家今日宣布發(fā)現另一個(gè)繞遙遠恒星飛行的行星，它是一個(gè)最多的行星系中的一員，而不是我們這個(gè)行星系。
