I have always considered that the true test of a machine is its practical utility in the hands of the common laborer.
Legal rules are not merely commands backed by threats.
经济景观是一个由不同等级的中心地组成的系统,每个中心地为特定区域服务。
生物学的魅力在于它的复杂性和解决方案的优雅。
水和空气,所有生命赖以生存的两种基本流体,已经变成了全球的垃圾箱。