在狭义相对论的学习中，“同时的相对性”最令人困惑、最难理解，根本原因在于如何理解时空的本质．本文通过精心设计案例的详细解析，说明对时间和空间的理解要紧密结合物质的运动．时间和空间是物质的内禀属性，只有在物质的运动及相互联系的物理过程中才能体现出时间和空间的性质．

In the study of special relativity, ‘simultaneous relativity’ is the most confusing and difficult to understand, and the fundamental reason lies in how to understand the essence of time and space. This article explains in detail through case studies that understanding time and space should be closely integrated with the movement of matter. Time and space are intrinsic properties of matter, and their properties can only be reflected in the motion and interconnected physical processes of matter.