“呃——Imagine spilling water—you can’t put every drop back exactly as it was. If this process could reverse, we could undo everything that has ever happened. But in real life, time and entropy can’t be turned back.”(想象一下洒出来的水——你不可能把每一滴水都放回原样。如果这个过程可以逆转,我们就可以撤销曾经发生的一切。但在现实生活中,时间和熵是无法倒流的。)