theory of canopy-heavens

例句：

1. 1.The theory of the canopy-heavens is a fundamental concept in astronomy.
   天穹理论是天文学中的基本概念。
2. 2.The theory of the canopy-heavens has been studied for centuries.
   天穹理论研究了几个世纪了。
3. 3. The theory of the canopy-heavens provides a framework for understanding the universe.
   天穹理论提供了一个理解宇宙的框架。