proper motion的用法和樣例：
例句
用作名詞 (n.)
- Risk the illegal website proper motion that establishs with stockjobber name to shut.
冒用證券公司名義設立的非法網站自行關閉。 - However, if its membership can be confirmed by proper motion and radial velocity determinations, the cause of light variation may not be pulsation.
但是，如果自行或視線速度測定證實為其成員星，那麼變光的原因也許不是脈動。
