star motions的用法和樣例：
例句
- Astrometry is not the only planet-hunting method to look for a star's motion as it is orbited by a planet.
當恒星附近有一顆行星的時(shí)候天體測量并不是唯一的一種通過(guò)觀(guān)察恒星運動(dòng)搜尋行星的辦法。 - But the earth is in motion relative to the sun, the sun is in motion relative to some other star, and so on.
但地球相對于太陽(yáng)運動(dòng)，太陽(yáng)相對于某些其他恒星運動(dòng)，等等。
