柠檬问题是指买家无法确定产品质量，因此只愿意支付反映平均质量的价格。

勿羡慕那些生活在愚昧“天堂”的人们，因为只有愚人才认为那里是幸福的。

What has destroyed every previous civilization has been the tendency to the unequal distribution of wealth and power.

The quarry industry must evolve with technology, or risk being left behind.

能源的未来在于多样化和适应性。