可持续发展不是一种选择；它是能源未来的必要条件。
I can resist everything except temptation.
The greatest obstacle to being heroic is the doubt whether one may not be going to prove one's self a fool; the truest heroism is to resist the doubt, and the profoundest wisdom to know when it ought to be resisted, and when it be obeyed.
解释：处于安全环境时要考虑到可能出现的危险，考虑到危险就会有所准备，事先有了准备就可以避免祸患。
事实上，今天的美国女性比历史上任何时候都拥有更多的权力和影响力。
Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious.
The universe is not only stranger than we imagine, it is stranger than we can imagine.