3. Everyone experiences time differently.
每个人对时间的体验是不同的。

This is true at the level of both physics and biology. Within physics, we used to have Sir Isaac Newton's view of time, which was universal and shared by everyone. But then Einstein came along and explained that how much time elapses for a person depends on how they travel through space (especially near the speed of light) as well as the gravitational field (especially if its near a black hole). From a biological or psychological perspective, the time measured by atomic clocks isn't as important as the time measured by our internal rhythms and the accumulation of memories. That happens differently depending on who we are and what we are experiencing; there's a real sense in which time moves more quickly when we're older.
从生物学和物理学角度来说都确有其事。物理学上，牛顿曾提出过经典的、普适的时空观，但后来爱因斯坦提出，人们身上时间的流逝跟他们在空间中的运动方式（尤其是当运动速度接近光速时）和引力场（尤其是靠近黑洞时）紧密相关。从生物学或心理学的角度来看，由原子钟计量的精确时间并不如人体内在节律和记忆所计量的时间那样重要。而受到个人身份和经历的影响，每个人的生物节律都是不同的。随着年龄的增长，我们确实会有“时间过得更快”的感觉。