theoretical nose of crossing

例句：

1. 1.The theory of relativity has revolutionized our understanding of space and time.
   相对论理论已经彻底改变了我们对时间和空间的理解。
2. 2. The study of quantum mechanics is a theoretical exercise in the realm of physics.
   量子力学的研究是物理学领域内的理论探讨。
3. 3.The project's success hinges on the feasibility of its theoretical implementation.
   该项目的成功取决于其理论实施的可能性。