随机实验是因果推理的黄金标准，但它们并不总是可行的。

I pray whoever reads this will be successful， keep fighting for success， the rich stay rich by spending like the poor and investing why the poor stay poor be spending like the rich yet not investing， Roar！！ Invest， earn and be successful.

采矿效率不仅仅是成本问题，更是减少环境影响的问题。

In every story, there is a piece of the writer's soul.

译文：天上的风云变化无常，不可预测，人间的事情难以估量，大多互相抵触。赏析：很多事情很难得到别人的认同和理解，只要我们问心无愧，行得正，不一定要在乎别人的言辞和态度。

无论头上是怎样的天空，我准备承受任何风暴。