解释：大部分药材都以新鲜为好，但艾草却以陈年的为佳，体现了药材使用的特殊性。

The end of history will be a very sad time. The struggle for recognition, the willingness to risk one's life for a purely abstract goal, the worldwide ideological struggle that called forth daring, courage, imagination, and idealism, will be replaced by economic calculation, the endless solving of technical problems, environmental concerns, and the satisfaction of sophisticated consumer demands.

Bringing computers into the home won't change either one, but may revitalize the corner saloon.

Success in agriculture starts with respecting the land and understanding its rhythms.

石材的真正价值在于我们如何改造它以供人类使用。