We often hear people say, "What's past is past. Let’s look to the future. "
我们常听人说：“过去的已经过去了，让我们展望未来吧！”
That's because what has happened has happened
这是因为已发生的事都已发生了，
and if we can’t do anything about it, it,s already a waste of time to dwell on the past.
如果我们无可奈何，那么怀念过去是浪费时间。
As the saying goes, "It's a waste of time thinking hard about the past. There's nothing you can do to change it. "
俗话说：“缅怀过去是无用的；过去的事你已无法逆转。”