We know that this is so,but all too often we recogenize this truth only in our backward glance when we remember what it was and then suddenly realize that it is no more.

• 我们知道事情就是这样，但是大多数时候，只有在我们回首往事，想起它的过去，突然意识到它已经不在是过去的样子，我们才会明白这个真理。