解释：只是一种声音就没有听头，只是一种颜色就没有文采，只是一种味道就不成其为美味，只是一种事物就无法进行衡量比较。

The great secret that all old people share is that you really haven't changed in seventy or eighty years. Your body changes, but you don't change at all. And that, of course, causes great confusion.

The historical sense involves a perception, not only of the pastness of the past, but of its presence.

在现代能源生产中，可持续性和效率必须齐头并进。