And that's a lot of the reason why we care so much about our careers and indeed start caring so much about material goods. You know, we're often told that we live in very materialistic times, that we're all greedy people. I don't think we are particularly materialistic. I think we live in a society which has simply pegged certain emotional rewards to the acquisition of material goods. It's not the material goods we want;
能源的未来不是要在化石燃料和可再生能源之间做出选择，而是找到确保可靠性、可负担性和可持续性的正确平衡。
数学不仅仅是关于数字、方程、计算或算法：它是关于理解的。
"The past is never dead. It's not even past."