Sirius

例句：

1. 1. The star Sirius is often used as a navigational aid.
   天狼星经常被用作导航辅助。
2. 2. Sirius is the brightest star in the constellation Ursa Minor.
   天狼星是小熊座中最亮的星星。
3. 3. The discovery of Sirius was a significant milestone in astronomy.
   发现天狼星在天文学上是一个重大的里程碑。