Risk management in mining isn't about eliminating all risks - that's impossible - but about understanding and mitigating them intelligently.
The United States is experiencing a crisis of political decay, with institutions that are increasingly dysfunctional and unable to address the country's challenges.
所以,即使做很困难的事情,也一定能够达到目的,没听说过想达到自己的愿望,而能回避困难的。 
弦理论提供了一个框架,使得量子力学和广义相对论能够和谐共存。