Yin

例句：

1. 1. The moon is the natural satellite of the earth.
   月亮是地球的自然卫星。
2. 2. The gravitational force between two objects attracts them towards each other.
   两个物体之间的引力使它们相互吸引。
3. 3. Gravity plays a crucial role in the formation of planets and stars.
   引力在行星和恒星的形成中起着关键作用。